METALLURGICAL CHANGES IN STEEL DUE TO CRYOGENIC

PROCESSING AND ITS APPLICATION

PRESENTED BY:JITULIN MOHARANAROLL NO:276227th SEM.,B.TECH

UNDER THE GUIDANCE OF:M/s SWARNALATA BEHERA

TALK FLOW

INTRODUCTION SOME PROMINENT ADVANTAGES “CRYOGENICS” AT A GLANCE A CRYOGENIC CYCLE METALLURGY OF CRYOGENIC TREATMENT APPLICATIONS “WHY” CRYOGENIC PROCESSING IS NOT WELLKNOWN CONCLUSION

INTRODUCTION

DERIVED FROM “KRYO”(COLD) AND “GENES”(BORN).

TEMPERATURE OF TREATMENT:BELOW 120K (-244F,-153C) AS DEFINED BY “CRYOGENIC SOCIETY OF AMERICA”.

MAJOR AIM:INCREASE ABRASION RESISTANCE AND FATIGUE RESISTANCE.

CONTD….

HAD LESS VALUE,NOW USEFUL DUE TO COMPUTER

MODELLED COOLING SYSTEMS. REDUCES THE CHANCES OF CORROSION. COSTS LESSER THAN PAINTING.

SOME PROMINENT ADVANTAGES

HOMOGENISES THE CRYSTAL STRUCTURE.REFINES THE SIZE OF GRAINS.PREVENT CONCENTRATED HEAT BUILD UPS.RESISTS THE FLOW OF DISLOCATION.CONVERTS RETAINED AUSTENITE TO

MARTENSIT. CONTD…

MECHANICAL PROPERTIES LIKE “MICROHARDNESS”,”TENSILE STRENGTH” ARE SAME ACROSS ANY CROSS SECTION.

RELEIVES RESIDUAL STRESS.PROVIDES A LONGER SERVICE LIFE .

CRYOGENICS AT A GLANCEHOW METALS BEHAVE AT VERY LOWER

TEMPERATURES.TEMPERATURE SCALES USED:RANKINE(R) AND

CENTIGRADE(C) 5R=(C+273.15)9ADDITIONAL COOLING EFFECT DUE TO CONDENSATION OF GASES.

CONTD…

PROVIDES STABILITY AND ABRASION RESISTANCE. EVERY STEP SHOULD BE CONTROLLED VERY CAREFULLY. NOT A HEAT TREATMENT PROCESS ITSELF.

A CRYOGENIC CYCLERAMP DOWN: 1. LOWERING THE TEMPERATURE OF THE

OBJECT TO BELOW -300F. 2. VERY SLOW PROCESS,USUALLY OF 6- 10

HOURS. 3. MAIN AIM: TO AVOID CRACKING OF THE

OBJECT.

SOAK: 1. HOLDING THE TEMPERATURE LOW. 2. ALSO A TIME TAKING PROCESS. 3. MAIN AIM: TO PROVIDE A MINIMUM

ENERGY STATE TO THE CRYSTALS.RAMP UP: 1. HEATING THE OBJECT BACK TO ROOM

TEMPERATURE. 2. CARE SHOULD BE TAKEN TO AVOID

CRACKING.

TEMPER RAMP UP: 1. HEATING UP AGAIN TO A PRE

DETERMINED TEMPERATURE. 2. MAIN AIM: TO REDUCE THE

BRITTLENESS OF FRESHLY FORMED MARTENSITE.

TEMPER HOLD: 1. HOLD FOR PROLONGED TIME 2. MAIN AIM: HOMOGENISE THE

STRUCTURE

METALLURGY OF CRYOGENIC TREATMENT

MARTENSITE BETTER RESISTS THE PLASTIC

DEFORMATION THAN AUSTENITE.CONCRETE EFFECT: SMALLER CARBIDE PARTICLES

WITIN THE BULK OF MARTENSITE AND LARGE CARBIDE PARTICLES PRODUCE MORE STRENGTH.

RELIEVES RESIDUAL STRESS

CONTD…

IMPARTS CORROSION RESISTANCE.

APPLICATIONSIN GUN BARRELS: 1. PREVENTS BENDING OF

BARRELS OF FIRE ARMS. 2. INCREASES WEAR LIFE,MAKES

CLENING EASY. 3. KNOWN AS

“CRYOACCURIZING”.

After cryo processing Before cryo processing

Actual Rugger M77 group at 100 yards

IN ENGINE PARTS: 1. SIGNIFICANT APPLICATION IN RACING CARS. 2. ENGINES TURN MORE FREELY. 3. PARTS DO NOT BREK AS OFTEN,NEITHER WEAR

FASTLY. 4. CONNECTING ROD FAILURE IS REDUCED. CONTD…

Cryogenically treated Non- Cryogenically

treated

Aluminum piston alloy structure

5. CRYOGENICALLY PROCESSED PISTONS HAV MORE WEAR RESISTANCE,HIGHER YEILD AND STRENGTH.

6.BETTER CORROSION RESISTANCE TO REACTIVE GASES.

IN COMPACT DISCS: 1. RESPONSE OF DISCS TO CRYOGENIC

TREATMENT IS NOT RESOLVED YET,BUT QUALITY OF SOUND COMING OUT OF IT IS BETTER.

INDUSTRIAL APPLICATIONS: 1. CUTTING AND MILLING TOOLS. 2. PUMP JACK GEARS,VALVES IN OIL AND

GAS INDUSTRIES. 3. DRILLING STEEL RODS AND BITS IN

MINING INDUSTRIES. 4. DENTAL AND SURGICAL INSTRUMENTS. 5. SAWS,DRILL BITS IN WOOD

FABRICATING.

6. 204 NO. OF MANUFACTURING

PLANTS,AFTER USING CRYOGENIC TREATMENTS ON STEEL,EXPERINCED FOLLOWING:

LIFE INCREASED BY 2X OR GREATER

50%

LIFE INCREASED IN SOME CASES,BUT WAS NOT UN AFFECTED IN OTHERS

18%

LIFE INCREASED IN SOME CASES,BUT DCREASED IN OTHERS

3%

NO EFFECT 24%NEGATIVE EFFECT 5%

WHY CRYOGENIC PROCESSING IS NOT WELLKNOWN?

ITS PRACTICE DIFFERS FROM ONE COMPANY TO THE NEXT.

PEOPLE USE CRYOCOOLERS FOR COOLING BEVERAGES BUT KNOW LITTLE ABOUT METALLURGY.

NOT ENOGH RESEARCHES.CHANGES ARE DIFFICULT TO EXPLAIN.RELATIVELY NEWER PROCESS.

CONCLUSIONPRODUCE IMPRESSIVE RESULT THAN IN

THE CASES OF CONVENTIONAL HEAT TREATMENT PROCESSES.

AFFECTS THE ENTIRE VOLUME OF THE OBJECT.

EXPECTED TO DEVELOPE WIDE APPLICATIONS.