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Nuances

General engineering steels

• Steels for carburizing
• Through hardening steels
• Maraging steels
• Steels for nitriding
  

  A&D Grade	Specifications			Chemical Composition			Mechanical properties
  	European standard	USA	Common designation	C		Cr	Mo	Heat treatment	UTS (N/mm²)	0,2% YS (N/mm²)	A (%)
  												GK3	31CrMo12			0.30		3.00	0.40	T + Rv 625°C	1000	850	18
  GK5	20CrMo12			0.20		3.00	0.40	T + Rv 610°C	1000	820	19
  GKH	33CrMoV12‑9	UNS: K24340		0.30		3.00	1.00	T + Rv 600°C T + Rv 660°C	1300 1000	1100 850	15 20
  GKP	32CrMoV5	UNS: K23280		0.30		1.40	1.20	T + Rv 640°C T + Rv 660°C	1250 1130	1175 1060	15 16
  LK3	41CrAlMo7‑10	UNS: K24065	NITRALLOY 135	0.40		1.80	0.25	T + Rv 625°C	1000	850	16

  A&D Grade	Specifications			Main Standards
  	European standard	USA	Common designation	AIR	AECMA	NF-EN/NF-EN-ISO/NF-A		WL	BS	AMS	ASTM		SUS	JIS
  				Standard	Standard	Symbol	Numerical	Standard	Standard	Standard	Grade	Standard	Standard	Standard
  GK3	31CrMo12			30CD12	FE‑PL1501, FE‑PL48 30CrMo12	31CrMo12 32CrMo12	1.8515 1.7361	1.8564
  GK5	20CrMo12
  GKH	33CrMoV12‑9	UNS: K24340		32CDV13	FE‑PL1504 33CrMoV12					6481
  GKP	32CrMoV5	UNS: K23280								6496 6497 6498
  LK3	41CrAlMo7‑10	UNS: K24065	NITRALLOY 135	40CAD6‑10		41CrAlMo7‑10	1.8509			6470

  A&D Grade	Specifications			Mechanical properties
  	European standard	USA	Common designation	Heat treatment	UTS (N/mm²)	0,2% YS (N/mm²)	A (%)	KCU (J/cm²)	KV (J)	KV -40°C (J)	KV -60°C (J)	Hardness HV	Hardness HRC
  GK3	31CrMo12			T + Rv 625°C	1000	850	18	150
  GK5	20CrMo12			T + Rv 610°C	1000	820	19	150
  GKH	33CrMoV12‑9	UNS: K24340		T + Rv 600°C T + Rv 660°C	1300 1000	1100 850	15 20	70 170
  GKP	32CrMoV5	UNS: K23280		T + Rv 640°C T + Rv 660°C	1250 1130	1175 1060	15 16		80 110
  LK3	41CrAlMo7‑10	UNS: K24065	NITRALLOY 135	T + Rv 625°C	1000	850	16	90

  A&D Grade	Specifications			Chemical composition
  	European standard	USA	Common designation	C	Cr	Mo	V	Al
  GK3	31CrMo12			0.30	3.00	0.40
  GK5	20CrMo12			0.20	3.00	0.40
  GKH	33CrMoV12‑9	UNS: K24340		0.30	3.00	1.00	0.20
  GKP	32CrMoV5	UNS: K23280		0.30	1.40	1.20	0.30
  LK3	41CrAlMo7‑10	UNS: K24065	NITRALLOY 135	0.40	1.80	0.25		1.00

  Key to heat treatment symbols
  Solution treated	H	Annealed	R
  Thermo-mechanical treatment	TM	Quenched and tempered	T+RV
  Sub-zero treatment	F	Solution treated and aged	H+V

  
  
• Steels for special applications