What is the properties of 40# steel?

40# steel is a high-quality carbon structural steel, 40# represents a carbon content of 0.40%, the actual content is 0.37% ~ 0.44%. High quality means that the content of P and S is required, the content of p must not be greater than 0.035%, the content of S must not Greater than 0.03%. Because this type of steel changes the properties of steel through carbon content, there are still differences between 40# steel, 35# steel and 45# steel.
Chemical composition of 40# steel

Element	C	Si	Mn	Cr	Cu	Ni	P	S
min.	0.37	0.17	0.5	-	-	-	-	-
max.	0.44	0.37	0.80	0.20	0.25	0.30	0.035	0.03

 
40# carbon steel has high strength, good machinability, medium cold deformability, poor weldability, no temper brittleness, low hardenability, easy to generate water quenching cracks, mostly used in quenched or normalized state, the two have similar overall performance After surface quenching, it can be used to manufacture parts with greater stress. 40# steel is suitable for the manufacture of crankshaft mandrels, transmission shafts, piston rods, connecting rods, sprockets, gears, etc. It needs to be preheated before welding. Slow cooling after welding. In many customers' orders, there are other foreign grades, 40# steel, the corresponding Japanese standard JIS grade is S40#C, and the corresponding American standard grade is SAE1040#. Basically, the chemical composition is similar. In the selection process, they can be directly produced using the national standard 40# steel.

Pre: Q355C Steel Material

Next: 15CrMo steel plate spot 2020