Materials 1045 4130 174 SS Procedure 1045 4130 Test and rec

Materials 1045 4130 17-4 SS Procedure -1045 & 4130 Test and record sample hardness Harden for (3) hour @ 870* C (1598 degree F) Quench in water Test and record as quench hardness Temper (2) hour @ 540 degree C (1000 degree F) Quench in water Test and record as tempered & quench hardness Procedure - 17 4 SS Test and record sample hardness Temper (3} hour @ 900 degree F (482 degree C) Air cool or fast air cool with fan Test and record tempered hardness What should the as quenched hardness be and why for 1045 & 4130? What should respective tensile strength be 1045 & 4130 @ tempering temperature Explain why 1045 & 4130 have to be tempered after being hardened. What should the hardness be for H-900 tempering temperature (17-4SS)? Why does 17-4 have to be put into-Condition A (annealed) prior to tempering? What happens if 17-4 SS is not annealed property? What is the tensile strength for H-900 tempering temperature? What is the relationship between tempering

Solution

solution:for 4,5,6,11,12

1)in the case of 1045 and 4130 alloy steel ,when steel undergoes hardening process by heting to high temperature,holding there for some time and fastly cooling to room temperature,then cooling curve will pass before nose of time temperature diagram and directly form martensite phase in microstructure which has high strength of all phases of steel.

2)but fast cooling will cause some of amount of residual of ferrite phase which is ductile in nature and fast cooling induce stresses in material and make martensite to be brittle and to make hard subsequent tempering is done and then slow cooling to room temperature will reduced stress but reduced hardness of martensite steel.

3)properties of 1045 steel and 4130 alloy steel are

for 1045 steel

brinell hardness number=163

tensile strength=565 MPa or 57.59 kg/mm2

hence relation between tensile strength and hardness is linear

T.S.=.3533*BHN

for 4130 alloy steel

brinell hardness number=217

tensile strength=560 MPa or 57.08 kg/mm2

hence relation between tensile strength and hardness is linear

T.S.=.2630*BHN

4)hence relation between hardness and tensile strength is linear and govern by above mention relation at this condition

5)relation between hardness and tempereing temperature for steel is inversely varying for temperature range of 200 c to 500 c and after that it varies slowly