2016In Plant Training Report

Submitted ByNishant singh tomar51892514031

In Plant Training Report

On

Railway Wheels factory

Submitted By The Students Of Polytechnic

In

Mechanical Engineering

Nishant singh tomar 51892514031

Submitted By :-

In Plant Training Carried Out At

RAIL WHEEL FACTORY Bela , Saran(Bihar)

AcknowledgementI would like to express my deepest sense of gratitude and reverence to my major guideand chairman of my advisory committee M.M.Singh Netaji subhas Institude ofTechnology, Amhara,Bihta,Patna,Bihar for his able guidance,critically going throught themanuscript and rendering me all the possible help during the entire Mechanicalengineer studies.

I am thankful to my minor advisor Sujeet kumar , Netaji subhasInstitude of Technology for providing all the needed instruction and guidance about myresearch work and thesis writing work and other member of my advisory committeeSushil kumar.NetajiSubhas Institude of Technology and Zeeshan sir of my institudefor their worthy suggestion,even willing help and unbiased attitude throughout thecourse of this investigation.

I also gratefully acknowledge the valuable helf, constant attentionand useful suggestion rendered by Mr. Ravi Bhushan , Mr. Rajendra Prasad singhand all the staff members of NSIT engineer university for their valuable guidance andco-operation throughout the course of my studies.

My vocabulary fails to get word to express my respect and senseof gratitude to my beloved family member;my mother,my father,my brothers,constantencouragement inspiration, prayer,moral,support and guidance.Lastly,I would like toexpress my enormous indebtedness and deep sense of gratitude to the God providingme spiritual exuberance and infinitum.

(Nishant singh tomar)

Abstract

This report contains the brief procedure carried out in RWF to produce

rail wheels . The materials required for the productions, processing

and also the test carried out on the components such that they do not

undergo any damages during working

Indian Railways is the largest railway network in Asia. The wheels and

axles for the entire Indian railways is manufactured and supplied by

RWF (Rail Wheel Factory).

.

Table of Contents

Company History

• Profile • Overview • Production

Wheel shop

• Forging Shop • Casting shop • Cleaning shop

Material Testing

• Destructive testing • Non-destructive testing

Company HistoryRail Wheel Plant, Bela is a subsidiary of Indian Railways. It is situated in BelaGramPanchayat, Dariapur Block, Parsa in Saran district of Bihar.[3] It was inaugurated in2008 by theformer Railway Minister of India, Laloo Prasad Yadav. It was built at a cost of 1,450crore (US$220 million).[4] It is spread over a land area of 165 acres.[5][6] Itsmanagement is under EastCentral Railway Zone headquartered in Hajipur. The project is being looked afterby Workshop projects/Indian Railways, Patna.The Rail Wheel Plant's construction, which started in July 2008, was a step to reviveindustrializationin Northern Bihar. Indian Railways made history by awarding this project as anEngineering Procurement & Construction (EPC) contract to Larsen & Toubro Limited(L&T) M/s Larsen & Toubro Limited. It was the first time in the history of Indian Railwaysthat a highly sophisticated factory was set up without any foreign collaboration. It waspossible because of the in-house capability of railway engineers and expertise of L&T.The construction division of L&T (ECC) was involved in civil & electrical works, whereasthe Railway Business Unit (an initiative of L&T in rolling stock projects) set up methodsand procedures along with interfacing of equipment. Working in close coordination withcontractors and sub-contractors, Indian Railways achieved completion of the projectwithin the stipulated time-frame of 40 months (24 months of the original time scheduleand additional extensions).It was a challenge for Indian Railways to start civil works in a difficult site which issurrounded by rivers on all sides. To add to complications, the elevation of plant waslower than the river bed. Because the soil was loose, stone columns were constructedto increase the load-bearing capacity of the soil. Additionally, Bihara is a remote areaso L&T deployed 24-hour security because therewas constant fear of unlawful activities by locals and Maoist insurgents.

Nearly 3000 workers were employed during peak construction period including 300highly skilled engineers of various specialties. The Rail Wheel Plant project wascompleted with a safety record of1 million safe man hours. This admirable safety record was achieved through a dailymorning pep- talk and vigilant site supervision by trained and qualified safety stewardsThe villages of Dariyapur Block specially Laloo Tola, Mushahari, Durbela, Babu Tola,and Kochwara were affected by the acquisition of land from farmers of these villages.The most land was of Awadhiya caste and rest was of Yadav, Bhumihar Brahmin and alittle of Rajput .Indian Railways compensated farmers for the acquired lands andpromised them jobs in the plant. The State Government in collaborationwith Power Grid Corporation of India founded the Sitalpur Power Grid in the year2000 to provide electricity to the plant and neighboring villages in a radius of 25km.The Rail Wheel Plant founded some institutions for its employee and members ofneighboring villages, especially Bela Gram Panchayat and Dariyapur:

Kendriya Vidyalaya, Bela (affiliated from CBSE Delhi) Railway College, Bela (affiliated from Jai Prakash University) Yamunachari High School, Dariyapur (State Government School affiliated from BSEB Patna) Government High School, Dariyapur (State Government School affiliated from BSEB Patna)

ProfileRail Wheel Plant, Bela has become a Production Unit of Indian Railways w.e.f

01.08.2014. It is situated at Bela in Dariyapur Block of Saran district

in Bihar (India). Foundation stone of this Plant was laid in 2008 by the then Minister for

Railways Shri Lalu Prasad Yadav. It is being built at an approx. cost of Rs. 1500 crores.

It is spread over a land area of 295 acres. The project work is being looked after by

Workshop Projects/Indian Railways, Patna. At present, the Project work is continuing

and wheel discs are being produced on trial production. The Rail Wheel Plant’s

construction started in July 2008. This plant is a step to revive industrialisation in

Northern Bihar

.Indian Railways made history by awarding this project as EPC contract to M/s Larsen

& Toubro Limited. It was for the first time in history of Indian Railways that a highly

sophisticated factory was set up without any foreign collaboration. It was possible

because of inhouse capability of Railway engineers and Expertise of World renowned

Indian company. It was a challenge for Railways to start civil works in such a difficult

site which is surrounded by river bodies from two sides. To add to the complication, the

elevation of Plant was lower than the river bed. Also the soil was so loose, Railways

made use of stone columning for increasing the load-bearing capacity of soil.

OVERVIEW

.

The Indian Railways are one of the largest in the world under a single

management. They employ the largest manpower as compared to any other

enterprise in the country. They also own the heaviest assets and rail track

length of over one-lakh kilometres and are operating the railways with nearly

5 300 locomotives, 39,000 passenger vehicles and 3.5 lakh freight cars. The

size and magnitude of the railways can be better appreciated when we realize

that their Railways run more than 1.5 lakh train kilometres every day carrying

nearly one crore passengers and nearly 67 lakh tons of originating freight

dally, there by earning over Rs.4 500 crores of revenue per annum. While on

the one hand the Railways have been striving hard to meet the transport

needs of the country and to provide more and more amenities, they have also

been struggling to improve the health of the railways and to rehabilitate its

aging assets. To achieve the astronomical results of performance mentioned

above It Is Imperative that the railways explore all possibilities of the country

becoming self-sufficient in all Inputs. Not only for repairs and rehabilitation of

the aging rolling stock but also for manufacturing additional rolling stock to

meet the Increasing demands the requirements of wheel are also increasing.

These are one of the heaviest components of the Railway

Wagons and coaches, which play the most crucial role towards safety.

Productions

Wheels RWF manufactures cast steel wheels by a controlled pressure pouring

process. In this process, the raw material used is pedigree scrap (old used

wheelsets, axles etc, rejected as unfit for use by the Railways). The scrap

steel is melted in Ultra High Frequency Electric Arc furnace. The correct

chemistry of molten metal steel is established through a Spectrometer. The

wheels are eventually get cast in the graphite moulds, which are pre-heated

and sprayed. After allowing for a pre-determined setting time the mould is spilt

and the risers are automatically separated from the cast wheel.

The wheel is then subjected to various heat treatments. The wheel undergoes

the process of cleaning, checking, peening and various stages of inspections.

The wheel produced by this process requires no machining except the

precession boring of heats central hole (hub) where the axle has to be fitted.

WHEEL SHOP

The first unit of Rail Wheel Factory is wheel shop where Railway wheels

are produced. The wheels of a vehicle are the circular objects which are fixed

underneath. It enables the vehicle to move along the ground.

The railway’s wheels are circular objects made up of alloy steel and weigh

about 500 kg. There is variety of railway wheels. All types are produced in the

same manner but they differ in their dimensions. The wheel sits on the wheel

seat of the axle.

In rail wheel factory, the wheel shop is divided into 3 portions where different

operations are performed on the wheel.

The Three parts are:

Melting Shop

Casting Shop

Cleaning Shop

Each shop is explained further in detail.

MELTING SHOP

In the wheel shop of Rail Wheel Factory, the wheels are manufactured by

casting process. For this process molten metal is required. Hence the first

process for the manufacturing of railway wheels in the wheel shop is Melting

of Metal scrap.

Melting is a process of converting the solid metal scrap into molten metal

which can be used for casting any shaped solid or hollow structure. When the

temperature is raised very high i.e., to a temperature above the melting point

of that particular metal, under a very sophisticated environmental condition,

the solid metal changes its phase into liquid. This is the basic principle of

melting.

The furnace used in RWF for melting is ELECTRIC ARC type of furnace and

the charge used for producing molten metal are rejected wheels, axles etc.

ELECTRIC ARC FURNACE:

An electric arc furnace utilizes the heat produced by the electric arc

generated between two conducting materials to melt the charge. It is used for

melting cast iron and steels. High thermal efficiency, rapid heating, close

temperature control and strict atmosphere are few characteristics of the

furnace that lead to the production of good quality metal.

Direct arc electric type of furnace is used in RWF wheel shop whose

construction is as follow:

The Furnace consists of a heavy steel cylindrical shell with a spherical

bottom lined with refractory of the furnace that supports the charge and the

walls are lined with magnesite bricks.

The furnace is built on a tilting platform that facilitates tilting of furnace

forward for pouring molten metal into ladles. The furnace can also be tilted

backwards for inspection, charging metal, flux, deoxidiser etc. and for removal

of slag through slag door.

The roof of the furnace is made of steel lined inside with refractory

bricks and can be clamped in position. Metal can also be charged from

furnace roof.

The roof is provided with 3 circular holes through which non-

consumable graphite electrodes are inserted. The electrodes can be raised

and lowered by means of guides and are usually water cooled to dissipate

heat. They are connected to 3-phase power supply.

Charge:

Scrap(rejected wheels)

The charge used for the production of railway wheels in RWF i

• The rejected wheels from wheel shop.

• Used axles and worn out wheels.

• The chips formed during machining of wheel

The main material composition of the scarp is alloy steels, carbon,

manganese and silicon.

Note:

The composition for casting of wheels can be altered by re-carburising or de-

carburising the molten metal in the furnace in order to obtain the required

wheel material composition.

Melting Process:

Arc furnace works on the principle that, when an arc is struck between the

electrodes and charge material, heat is generated due to the resistance

offered by the metal charge.

❖Level the furnace, remove the roof mast lock pin, raise the electrode and

then raise the roof of the furnace.

❖Charge approximately 900 to 1200kgs of claimed lime and 200 to250kgs of

claimed petroleum coke/graphite powder.

❖ Charge scrap wheels or metal cakes/skull or risers with the help of

magnet (2-2.5MT approximately)

❖ The electrodes are lowered down. On supplying the necessary current

and voltage, an arc is produced between the electrode and the charge

material.

❖ The gap between the electrode and charge is maintained by regulating

the movement of electrodes so that the arc remains between them and bums

continuously melting the charge material.

The flux melts and forms a slag that floats on the surface of the liquid metal.

The slag prevents oxidation, refines the metal and protects the furnace roof

from excessive heat.

REMOVAL OF SLAG:

After the liquid metal has been achieved the desired

temperature, the electrodes are raised to extinguish the arc and the furnace is

tilted backwards to remove the slag.

After 45-55minutes of arcing, start emptying the scrap through slag door with

oxygen lancing pipe. Spread dolomite over the cleaned slag door. Clear slag

door scrap. Remove full slag before the temperature is 1630 degree Celsius.

If the slag is sluggish, shovel 25 -30kgs of fluorspar on the slag.

❖ Temperature must be controlled so that the maximum slag is removed

by 1650 degree Celsius. Allow only thin layer of slag on the metal surface.

❖ Care must be taken not to remove the metal through slag door

throughout the slagging operation. Keeps the slag door clean by removing the

slag metal jam using pipe or rod.

❖ After almost all first slag is removed add Ferro-manganese at around

1650 degree Celsius and 150kgs of reducing slag mixture into the furnace to

make the slag reducing.

TAPPING OF MOLTEN METAL:

❖ Once the slag is taken out and the chemical composition of the molten

metal is tested and is same as required lift the ladle from John Mohr Pit (JMP)

with the help of crane and pours the molten metal to the ladle from the

furnace.

❖ Insulation powder is thrown into ladles to prevent radiation loss of liquid

metal.

❖ Excess molten metal which cannot be poured into the ladle may be

emptied into pigging pot or dirt floor.

Note:

The sample of molten metal is taken from the furnace at different temp.

and is tested for its composition and there by its properties by spectrometer

analysis.

The composition is altered de-carburising or re-carburising of molten metal.

RE-CARBURISING OF METAL

Keep the required quantity of graphite powder ready in small quantities,

filled in gunny bag; maintain the bath temp. around 1640 Celsius

minimum

Lower the electrode column into the molten bath, such that the

electrode is just inside the bath. Introduce the graphite powder into the

molten bath, near the electrode column through the slag door.

Push the cake fallen on door inside the furnace metal bath by rabble.

Put on the powder in whichever tap is required.

After 3-4 minutes of arcing, mix the bath thoroughly using metallic

rabbles.

Insure that the bath is uniform and no graphite powder is floating on the

top of the bath. Take the sample with the slag pre coated spoon from

deep inside the bath. After 3-4 min take one more sample in the similar

way.

DECARBURISING OF METAL :

The temperature of the metal must be maintained around 1630-1640 Celsius.

Coat the front end of oxygen pipe with furnace slag.

Insert the slag coated oxygen lancing pipe into the bath through the slag door

and blow the bath with oxygen at 5-6kg/cm depending on the carbon to be

reduced. After the oxygen blowing add 10-15kg of Ferro silicon to take care of

high oxidised metal, when necessary

Add 30-40kgs of Ferro manganese or silicon manganese to raise manganese

level in the bath and to take care of extra oxygen in the metal. Put on power.

Mix the bath thoroughly with the rabble. After 3-4 min of arcing, take the

sample from deep inside the bath for test. Again after 3-4 min take another

check sample.

The ladles are then taken into JMP from where the metal is poured into the

cope and drag assembly for casting.

Note:

There are three electric arc furnaces in RWF and two JMP

For each heat the furnace produces 20tonnes of molten metal in a

period of one hour , which is used to cast 30 Wheels

The furnace temp during melting is set to 1720 Celsius and during

pouring into ladle; the temp of molten metal is around 1610 Celsius.

CASTING SHOP:

In this part of the wheel shop the molten metal is poured into cope and drag

assembly, later the caste wheel is separated from cope and drag assembly and is

made to undergo certain heat treatment process.

CASTING:

The casting process begins with pouring of molten metal into cope-drag assembly, a

small period of air cooling and finally separating the cope-drag assembly to obtain

the caste wheel.

❖ The ladle containing the molten metal placed in JMP is brought into the place

of pouring and graphite powder is sprayed into molten metal to prevent temperature

loss.

❖ Cope and drag made up of graphite material is assembled and it is also

brought near the place of pouring.

❖ This cope-drag assembly is placed on the covering of the ladle which contains

a centre circular hole. This hole houses the — pipe through which molten metal gets

into the cope-drag assembly.

❖ When external air pressure is applied on the covering of the ladle, the liquid

metal with high pressure comes out of the ladle through the centre — pipe and gets

into the cavity present in cope-drag assembly.

❖ Once this cavity is filled with molten metal, a graphite stopper present in the

cope and drag assembly will fall down to the bottom of the drag and prevents the

further flow of liquid metal from ladle into cavity. Also it prevents the liquid metal

flowing back to ladle from cavity.

❖ The pouring of molten metal for each wheel takes about 80 sec and 30-31

wheels can be cast in each heat.

❖ Once metal is poured, paddy husk is added to the assembly through riser

holes to prevent sudden drop in temp of molten metal which otherwise would

produce cracks in the surface of the wheels.

❖ After 11 minutes of air cooling, the cope and drag assembly is split and the

caste wheel is obtained which is placed In Kiln where the wheel is subjected to

controlled air cooling.

❖ The separated cope and drag are sent separately and cleaned in various

ways:

First the metal present in sprue and riser are taken of the cope and later both cope

and drag and sand washed to take out every little metal present and also to produce

clean and finish surface so that it can be used for next casting.

SPRUE WASHING:

After the controlled air cooling the wheel coming out of the kiln is at a

temperature of about 400-600 degree Celsius.

It contains a little part of the runner and riser which is not removed

during splitting. The part must be removed before the further cleaning of the

wheel.

This is done in 2 ways:

1. Sprue grinding.

2. Induction process by electrode.

SPRUE GRINDING

In this method, the excess sprue material is removed by using

grinding wheel.

A grinding wheel mounted on the horizontal spindle is brought

on the caste wheel and hence the excess material is removed

by the abrasive action of the grinding wheel.

INDUCTION PROCESS

In this method a carbon electrode with copper coating is used to

remove the excess sprue material.

Once the electric current is sent through the electrode it

produces a strong electric arc between the carbon electrode and

the wheel. The heat produced by this arc is more than enough to

melt and vaporize the excess metal.

NOTE:

The temperature of the wheel should not be less than 380 degree

Celsius before entering sprue washing.

The long rod placed in the centre during casting is cut just before

sprue wash by grinding plate.

HUB CUTTING:

The centre portion of the wheel, where the axle fits in, need to be

bored in order to remove the caste portion from the wheel. This is done by up

cutting process.

The hole is initially bored for a diameter lesser than required during

this process using Hub Cutting Machine. Hence the process is

also called Hub cutting process.

The oxy-acetylene gas flame coming out of the nozzle at high

pressure and velocity is used for hub cutting.

The part of the pipe inserted during casting remains inside the caste

wheel after being cut at both the edges. This is called Pilot hole.

This hole is initially cleaned using pneumatic air, so that the hub

cutting process can be begun from this portion.

The oxy-acetylene gas flame is first directed to the pilot hole and

then moved along the radius and finally moved in a circular shape.

Hence the circular hub which is being cut falls after the arc

completes a circle of required radius.

NOTE:

• The nozzle of the machine need to be regularly changed to prevent hub not falling

situation i.e., if insufficient flame is supplied for cutting due to defects in the nozzle,

the hub is not completely cut through the whole depth of the wheel. Hence, the cut

portion will not fall after complete circular path of the flame

The distance of 8-12mm must be maintained between the nozzle tip and the back

hub face for proper cutting action.

HEAT TREATMENT

It is defined as an operation or combination of operations involving heating and

cooling of a metal/alloy in solid state to obtain desirable conditions or proportions.

OBJECTIVES OE HEAT TREATMENT

To eliminate residual stresses that is present in the axle during

forging and subsequent cooling.

To homogenize the structure of the metal of forging.

To impart, to the axle that degree of hardness, this makes it most

easy to machine.

To improve strength, toughness and other mechanical properties of

the forged axle.

NORMALISING:

The wheels after hub cutting remain at a temperature of about 400

degree Celsius. It is now sent into the Rotary Hearth Furnace for

Normalising process. Normalising process helps to maintain proper

grain size which is the main requirement for various properties of

the wheel

• The rotary hearth furnace used for normalising has 7 zones.

First 4 zones are called as pre- heating zones, where the outer

Layer of the wheel and a few inner layers get heated.

• The next 3 zones are called Soaking zone where in the heat

spreads uniformly including the core of the wheel.

• The temperature of these zones varies for different types of

Wheel.

E.g.: for BOXN wheels

Zone1 and 3 is 968 degree Celsius

Zone 3 to 7 is 938 degree Celsius

• The fuel used in rotary hearth furnace is High Speed Diesel.

• Each wheel remains in rotary hearth furnace for a duration of 1.5

hours before coming out.

• The temperature of the wheel coming out of the furnace is

around 950 degree Celsius.

Rotary Hearth Furnace

QUENCHING:

During the movement of the train, the rim portion of the wheel is in

contact with the rail and hence it is this portion that is subjected to

more wear and tear. Therefore this rim of the wheel must be harder

than the other parts of the wheel. This hardening is done by

quenching process.

High pressure jet of water is made to fall only on the ream portion of

the wheel for about 6-8 minutes. This increases the hardness of the

ream portion up to a depth of 5-8mm.

TEMPERING:

Since the wheels are manufactured by casting process, there are

chances of internal stresses being induced in the interior of the

wheel. These stresses are very dangerous and may also damage

the wheel during working. In order to remove these stresses from

the wheels, they are sent into Draw Furnace where the wheel

undergoes tempering process.

• The Draw furnace consists of 8 zones maintained at 500 degree

Celsius each.

• Each wheel once entered the Draw furnace remains inside for 2

hours before coming out of the furnace.

• The Draw furnace in RWF is run using high speed Diesel and

has a capacity of 40 wheels.

HUB QUENCHING:

During the assembly of the wheels with axels there are chances of crack

formations in the hub portion. Hence this portion needs to be hardened. This

hardening of the hub portion is done by Quenching Process.

High pressure jet of water is sprayed only on the interior of the hub during this

process. Hence the hub portion becomes harder after this process and the chance of

crack portion is totally reduced.

The wheel after hub quenching has a rough surface and is air cooled. The wheel

need not be air cooled separately, they are sent into storage yard after hub

quenching. Wheels are taken from storage yard as and when required and is

subjected to further cleaning and finishing process.

WHEEL FINAL PROCESS SHOP

CLEANING:

The Wheel coming out of the casting shop has a rough, uneven surface these

wheels need to be cleaned and finished before its usage. This cleaning, finishing and

certain tests are conducted in this cleaning shop.

The operations carried out on the wheel in cleaning shop are discussed below:

SAND BLASTING/STEEL BLASTING:

The surface of the wheel may contain dirt, ashes and even dust particles formed

during storing; also the wheels contain scales formed during heat treatment process.

This unwanted dust must be removed In order to obtain a clean surfaced wheel.

Steel blasting is the first process carried out in the cleaning shop.

In this process, tiny spherical metal particles with high velocity are made to strike the

surface of the wheel.

Due to the impact of these particles the surface dust present on the wheel gets

removed due to the abrasive action.

Hence the surface cleaned wheel is obtained after this steel blasting process.

After this steel blasting, the wheel is made to undergo two tests namely Ultra

Sonic test and Magnaglo test.

Only those wheels passed in these test are sent to further processing and the

wheels with defects are sent back to machining accordingly. The rejected wheels are

sent to scrap yard and is recycled.

WARPAGING:

The wheels during casting and heat treatment process remains at high

temperature. During this high temperature there are chances of wheel undergoing a

little bending. But this bending of wheels above certain limits is undesirable for the

working of the wheel.

The Warpaging process includes the balancing of the wheels from which the

defects relating to the shape of the wheels can be detected.

If the detected defects in the shape like bending of wheels etc. are more than

the limiting value, wheels are rejected.

SHOT PEENING:

Peening is a process very similar to steel blasting process.

Here tiny spherical steel particles are made to strike the surface of the wheel

at high velocity.

In case there arc surface cracks, when the steel particle strikes the cracked

surface at high velocity, they will fill the gap and help to remove the surface

defects.

Peening process also removes the surface stresses.

Each wheel undergoes peening process for minimum of 1 minute.

HUB BORING:

This is the rough boring operation carried out on the wheel before it is sent into

assembly shop.

During hub cutting, the centre hole generated is of a smaller diameter when

compared to the required diameter.

This hole need to be enlarged for the axle to fit in. This hole enlarging is done by the

boring process

o A square shaped carbide tool is used for this operation

o The hole of 3mm lesser than the axle wheel seat diameter is produced

during this process.

o The hole produced has a rough surface finish.

This completes the manufacture of railway wheels. Thus the wheel after boring

comes out of the wheel shop and is ready to be assembled along the axle and hence

ready for working.

TESTING OF MATERIALS

Welds, casting's and forgings are tested for one or more following

purposes.

o To asses numerically the fundamental mechanical properties like ductility,

malleability, toughness etc.

o To determine data i.e force deformation values to draw upsets of specification

upon which engineer can base his design,

o To determine the surface or sub surface defects in process parts.

o To check chemical composition.

o To determine suitability of the material for a particular application.

Tests on jobs can be broadly classified as

1. Destructive tests:

After being destructively tested, the component or specimen either

breaks or remains no longer useful for further use.

E.g. tensile test, impact test etc.

2. Non- Destruction tests

A component does not break in non destructive testing and even being

tested so it can be used for the purpose for which it is made.

E.g. magnetic particle inspection, ultrasonic testing etc.

Destructive Testing Physical section will carry out various metallurgical tests on

wheels, axles, consumables, maintenance spares accessories

and failure investigations.

The test shaft be carried on sample basis collected from the lot,

to check the suitability of the product or component for its

intended purposes or service, Based on the tests conducted on

the samples collected from the materials can be assessed to its

fitness to use further or not.

Importance of These Test

Tests are required to meet specifications. Specifications are

drawn internationally to cut down the manufacturing costs and to

avoid catastrophic online failure of the product. Specifications

are prepared uased on some test parameters which in turn gives

an idea of the component to serve the purpose. Ultimately the

result is pre-assessed of the product behavior in service.

TESTS CARRIED OUT

Since the wheels are produced by casting process, there is lot of

stress induced during solidification of the molten metal. These

are not good for working of wheels, hence to check the limiting

stress tests are carried out.

CLOSURE TEST : Radial saw cut analysis technique is used to measure the bulk

circumferential residual stress levels in rail road cast steel

wheel. With this technique the opening or closure of the saw cut,

at the flange tip is monitored as a function of the radial saw cut

depth.

HARDNESS TEST : Hardness survey conducted on wheel slice cut from the cast

wheel to asses the trend of hardening effect and its zone after

Quenching of wheel Hardness pattern will be checked on the

slice for every 30 mm approx. by using hardness tester.

TENSILE STRENGTH : In tensile testing, the ratio of maximum load to original cross

sectional area is also called the ultimate strength. This test M

give an idea of material strength obtained by proper process

adopted of steel making and its effective heat treatment done.

Test will be carried out by turning to the standard test method

and breaking by using tensile testing machine.

YIELD STRENGTH : The stress at which a material exhibits a specified deviation from

proportionality of stress and strain. The test will conducted on

integral part of UTS. This yield point is the first stress in a

material, and usually less than maximum attainable stress at

which an increase in strain occurs with out an increase in stress.

This point will be noted down while doing UTS.

ELONGATION : In tensile testing the increase in gauge length is measured after

the fracture of test specimen with in the gauge length. This test

will be measured after breaking of the specimen. This will

indicate the ductility of the material.

REDUCTION IN AREA : The difference, expressed as the percentage of the original

area, between original cross sectional area and that after

straining the specimen in tensile testing. This represents the

ductility of the material.

GRAIN STRUCTURE : Grain size are reported in terms on number of grains per Unit

area or volume average diameter, or as grain size number

derived from area measurements. This will be done as per

standard procedure method by using optical microscope at 100X

and compared to known ASTM charts respectively. The

structures of Polished and etched metals as revealed by a

microscope at a magnification greater than 10X. This indicates

the type of structure having the material. The test reveals the

casting defects of the Material like porosity, shrinkage etc this

test is done by surface Prepared and acid etched and viewed

not by exceeding 10X magnifications.

Impact Test: A test to determine the behaviour of the material when subjected to high rates of

loading, usually in bending, tension or torsion. The loads that are suddenly applied to

a structure are known as shock or impact load. One effect of this load is to produce

stress waves. These loads produce rapid build up of stress and effect the resisting

properties of the material. The property of a material is associated with work required

to cause rupture. Most comonly used impact tests are – izod and charpy tests.

IZOD IMPACT TEST: The test consists of breaking by one blow from a swimnging hammer under specified

conditions. A notched test piece gripped vertically with the bottom of the notch in the

same plane as the upper face of the grip. The blow is struck at fixed position on the

face having the notch. The energy is determined.

CHARPY IMPACT TEST: The test consists of breaking by one blow by a swinging hammer under specified

conditions. The test piece is U-notched in the middle and supported at each end.

The energy absorbed is determined from the impact value obtained.

HARDNESS: The term hardness is resistance to scratching, abrassion or cutting.the hardness

tests are carried out for the purpose of checking physical condition of a product.

These tests help to have a quality control of the product.

The resistance of the metal is usually measured by indentation. Various hardness

tests are employed such as brinnel, rockwell and vickers. This hardness determines

the material characteristics.

NON DESTRUCTIVE TESTING

ULTRA SONIC TESTING

The principle of this test is the velocity of Ultra Sonic Waves

(high frequency sound waves) varies in different medium. In axle

machine shop the Ultra Sonic Waves are made to pass through

the axle. The velocity of these waves varies in different metal

medium. When the waves are sent; if they come across metallic

and non- metallic inclusions the velocity varies which can be

detected through a computer connected to the ultra sonic testing

machine. While propagating, if the waves come in contact with

the cracks, they reflect without passing through them This

change in wave signal is detected on the computer. The axles

with cracks and non-metallic inclusions are if possible corrected

else it's rejected.

The ultra sonic testing is done twice in the axle machine Shop.

First when axle comes out of STATION 1 (Le. after end milling,

centering and cup turning). Here the waves are sent in

horizontal direction from two end surfaces so that interna!

vertical cracks can be detected.

Second when the axle id out of rough turning. Here the waves

are sent in vertical direction along the whole length so that

lnternal horizontal cracks can be detected It is called Radial

Ultrasonic Testing

NOTE :

o For detecting vertical cracks the Ultra Sonic Waves must be sent into the work

piece via a medium. And grease serves as a medium helping the waves to

pass through the work piece from the source

o For detecting horizontal cracks. water acts as medium for the waves to pass

from the source to the axle Both tests are earned out for about 8-10 hrs

MAGNETIC PARTICLE TESTING :

This test is done to a completely finished axle just before it enters the

assembly shop where assembling of wheel and axle takes place. This test is

mainly to detect surface cracks. In this test, magnetic particle powder is mixed

in oil and is poured on the body of the axle which is held in place by the

chucks. DC current is used and the axle acts as a permanent magnet until the

current flows through

Then Ultra Violet rays are incident on the axle. If no surfaces Cracks are

present then UV rays are reflected back else green light is effected. The axle

with cracks are rejected or else sent to heat treatment depending up on the

size of the crack.

Generalised Working Chart (Wheel)