GB/T6402-2008 / SEP921-84.  ASTM A388
	HEAT TREATMENT SPECIFICATION & MECHANICAL PROPERTIES:
	
		Tenlise strength  ≥966N/mm2  yeild strength ≥793N/mm2 
	
		Elongation ≥13%  reduction of area ≥45% 
	
		Impact test v notch, radial direction ≥55J(20℃)
	
		Hardness : 
	
		285-341HB 
	
		Grain size (ASTM112) ≥5 or fine .
	
		Non-metallic inclusion as per ASTM-45 method A: 
	
		A B C D  ≤2.5 ≤2.0 ≤1.5 ≤2.0 
 
	DELIVERY CONDITION : as per drawing.