4140QT SCM440 1.7225 Alloy Steel
4140QT SCM440 1.7225 Alloy Steel
4140QT SCM440 1.7225 Alloy Steel
4140QT SCM440 1.7225 Alloy Steel
4140QT SCM440 1.7225 Alloy Steel

4140QT SCM440 1.7225 Alloy Steel

42CrMo4 Mechanical property Tensile strength σb (MPa) : ≥1080(110) Yield strength σs (MPa) : ≥930(95) Elongation δ5 (%) : ≥12 Section shrinkage (%) : ≥45 Impact power Akv (J) : ≥63 Impact toughness value αkv (J/cm²) : ≥78(8) Hardness: ≤217HB Specimen size: specimen blank size is 25mm Heat treatment specification and metallographic structure Heat treatment specification: quench 850℃, oil cold; Tempering 560℃, water cooling, oil cooling. Metallographic structure: tempered sorbite.

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Product Introduction

4140QT SCM440 1.7225 Alloy Steel

42CrMo4 steel is ultra-high strength steel, with high strength and toughness, hardenability is also good, no obvious tempering brittleness, high fatigue limit and resistance to multiple shocks after tempering treatment, low temperature impact toughness is good. The steel is suitable for the manufacture of large and medium-sized plastic molds requiring a certain strength and toughness, and the surface quenching after tempering is usually used as the heat treatment program.

Processing

Forging

Preheat the steel carefully, heat to 1150 oC – 1200 oC maximum, hold until temperature is uniform throughout the section.

Do not forge below 850 oC.Following forging operation the work piece should be cooled as slowly as possible.

AISI 4140 Steel Grade Heat Treatment

Annealing
Heat ASTM 4140 steels to 800 oC – 850 oC, hold until temperature is uniform throughout the section and cool in furnace.

Normalizing
Heat steel alloy 4140 to 870 oC – 900 oC, hold until temperature is uniform throughout the section, soak for 10 – 15 minutes and cool in still air.

Tempering
Re-heat 4140 grade steel to 550 oC – 700 oC as required, hold until temperature is uniform throughout the section, soak for 1 hour per 25 mm of section, and cool in still air.

Hardening of AISI Alloy Steel 4140

AISI alloy 4140 steel bar, plate and square can be hardened by cold working, or heating and quenching.

SAE 4140 alloy steel is usually supplied ready heat treated to hardness in 18-22 HRC. If further heat treatment is required, then heat to 840 oC – 875 oC, hold until temperature is uniform throughout the section, soak for 10 – 15 minutes per 25 mm section, and quench in oil, water, or polymer as required.

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