Today, one US customer asks for 4140 steel plate, and he complains that the current material is too soft to machine. He needs ASTM 4140 alloy steel plate with higher hardness. I tell him we can supply 4140 pre hard plate directly out of inventory immediately. He is very interested in those prehard 4140 plate.
If it’s supplied as rolled condition, 4140 steel plate is with low hardness, not higher than 230HB. So, when some customer needs higher hardness for 4140 alloy plate, AISI 4140 plate material IN as rolled / hot rolled without harden heat treatment, is not suitable for you.
If you need alloy plate 4140 material with higher hardness, you can choose to inquiry or buy 4140 prehard plate directly. The prehard plate also called PH 4140 plate is supplied at 28-32HRC, some customer can accept 34HRC max. This is widely acceptable for this hardness. If you need even higher hardness, you need to do machining first with raw material plate, to get your desired blocks or pieces. Otherwise, it will be very difficult to do further machining with very higher hardness. You can do harden treatment to achieve even higher than 40HRC for 4140 alloy steel plate.
However, some customers also needs ASTM 4140 plate or flat with very low hardness. They don’t need higher hardness. Then they need to buy 4140 annealed plate. Hot rolled 4140 plate can be annealed heat treated to lower than 220HB usually. With lower hardness, it will be easy to do machining for some applicants.
So, you need to choose the right supplier for the right 4140 steel plate, for different hardness requirements. If you need ASTM 4140 prehard plate, Otai keeps 4140 plate inventory with immediate shipment. Contact us by Email or WhatsApp anytime. You can also check our 4140 steel plate Q+T inventory list here.
