4140H Steel

The main difference is that the 4150 steel has ten (10) additional "points" of carbon content, and ten (10) points =1%. The 4150 might cost a bit more due to the additional carbon, but it would not be much more at all. The 4150 will become harder after heat-treatment because of the higher carbon content. The designation of "H" band typically means the steel is hot-rolled.

Both the 4140 and the 4150 are triple-alloy steels of excellent hardenability and depth. I guess the choice would be determined by the end use. Do you need the extra hardenability of the 4150, or will the 4140 suffice?

Ing. Robert Forbus

Forbus

"10 points" means 0,1% carbon, not 1%. The nominal carbon content for 4140 steel is 0,4% C and for 4150 is 0,5% C.

"H" refers to the "Hardenability". Check hardenability of steels in the SAE Handbook or ASM Handbook.

"H" does refer to the "Hardenability" but more specifically "H" steels are guaranteed by the supplier to meet established hardenability limits for specific ranges of chemical composition. When an H-steel is specified, the steel producer shows on the shipping documents or by some other acceptable means, the hardenability characteristics of the steel heat involved. The heat hardenability is determined from either a cast or forged end-quench test bar.

Both 4140 and 4150 steels are available in H grade.

Thanks, Guest. When I posted it was about an hour after the end of the second shift and my brain was not working very well! Thanks for the correction to my comment.

Ing. Robert Forbus

parerea mea este ca al doilea are mare dreptate pentru ca 0,1%C inseamna mult fatza de 0,4%C , si binenteles al doilea trebuie utilizat, cu toate ca e mai scump din proprietatile impuse la selectia materialului iesindutzi astea doua iar cel mai bun nu e todeanua si cel mai ieftin:))

check this web site www.matweb.com

The difference is the Carbon.4150 include more carbon 0.1% than 4140.

Our factory usually manufacture gear with 4140/4150.they have good performance after heat treatment.The hardness is more than 60 HRC.

xinlaibj@126.com

This is for the USA.Very low price,good quality,delivery.

It's mainly different in the chemical composition for the 4140 steel and 4150 steel grades.

You can see the below differences: