50, 55 high-quality carbon structural steel - Alloy structural steel

Chemical composition:

Trademark	Chemical composition
	C	Si	Mn	P	S	Ni	Cr	Cu
	C	Si	Mn	≤
50	0.47～0.55	0.17～0.37	0.50～0.80	0.035	0.035	0.30	0.25	0.25
55	0.52～0.60	0.17～0.37	0.50～0.80	0.035	0.035	0.30	0.25	0.25

Mechanical properties:

Trademark	The sample blank Size / mm	Heat treatment process			Mechanical properties					Delivery status hardness of steel / HBS
		Normalizing	Quench	Tempering	σ_b/MPa	σ_s/MPa	δ₅(％)	ψ(％)	A_k/J	≤
		Normalizing	Quench	Tempering	≥					Without heat treatment	Annealed steel
50	25	830	830	600	630	375	14	40	31	241	207
55	25	820	820	600	645	380	13	35		255	217

Characteristics and Uses:
50: requirements for the manufacture of high wear resistance, dynamic load and the impact of little parts, such as casting gear, rod, roll, etc.; making relatively minor springs, agricultural digging on the Plowshare, heavy-duty spindle and shaft, and manufacturing castings.
55: for the manufacture of connecting rods, rollers, gears, flat springs, wheels, rims, etc., also can be used for casting.