Chemical Composition Of SCM430 Steel

SCM430 steel is a chromium-molybdenum alloy steel as per Japan Standard. JIS SCM430 steel contains a lower carbon content but provides better weldability comparing with SCM440 Steel. It is frequently applied to the gas & oil area.Typical applications include components such as valve bodies,pumps and hydraulic cylinder rod fittings.

SCM430 Round Bar Chemical Composition

Standard	Grade	C	Si	Mn	P	S	Cr	Mo
AISI 4130	SAE 4130	0.28-0.33	0.15-0.35	0.4-0.6	≤0.035	≤0.04	0.8-1.1	0.15-0.25
EN10083	25CrMo4 / 1.7218	0.22-0.29	≤0.4	0.6-0.9	≤0.025	≤0.035	0.9-1.2	0.15-0.3
ASTM A29	4130	0.28-0.33	0.15-0.35	0.4-0.6	≤0.035	≤0.04	0.8-1.1	0.15-0.25
JIS G4105	SCM430	0.28-0.33	0.15-0.35	0.6-0.85	≤0.035	≤0.04	0.9-1.2	0.15-0.3
GB 3077	30CrMo	0.26-0.33	0.17-0.37	0.4-0.7	≤0.03	≤0.03	0.8-1.1	0.15-0.25

SCM430 Round Bar Forging

Forging temperature of AISI 4130 steel should be carried out between 950℃-1200℃,The lower the forging-ending temperature ,the finer the grain size .Hold suitable time for the steel to be uinformly heated before forge, but don’t forge below 950℃.AISI 4130 steel should be cooled as slowly as possible after forged.

SCM430 Round Bar Heat Treatment

4130 Annealing

AISI 4130 steel can be annealed to relieve stress after forging ,and obtain a good structure suitable for machining,Annealing temperature should be carried out between 800℃-850℃, hold suitable time for the steel to be heated uniformly. Cool slowly in the furnace.

4130 Normalizing

Normalizing is used to refine the structure of forgings that might have cooled non-uniformly after forged,and considered as a conditioning treatment before final heat treatment.Normalizing temperature for AISI 4130 steel should be carried out between 880℃-900℃. hold suitable time for the steel to be uniformly heated to complete the ferrite to austenite transformation.Cool in still air.

4130 Tempering

Tempering is usually carried out to relieve stresses from the hardening process, and will optimize hardness and mechanical properties. The actual tempering temperature will be chosen to meet the required properties.Heat the AISI 4130 carefully to a suitable temperature ,usually between 400℃-570℃, soak at the temperature for 2 hours per 25mm of ruling section, then cool in air.The lower the tempering temperature the greater the strength. However, Tempering between 250-375°C is not advised as tempering within this range will seriously reduce the impact value.

Hardening of SCM430 Round Bar

This heat treatment will obtain martensite structure after quenched,it will increase the surface hardness and strength. AISI 4130 steel should be carried out between 870℃-890℃, hold suitable time for the steel to be thoroughly heated, then quench in oil, or water.Tempering should be followed immediately after quenched.