A Guide to SCM Steel CNC Machining

Characteristics of SCM Steel

SCM steel is an alloy steel based on carbon steel with the addition of 0.9% to 1.2% chromium (Cr) and 0.15% to 0.3% molybdenum (Mo). It is hardenable through heat treatment, resulting in high tensile strength and hardness, and is typically suitable for applications requiring greater strength than standard carbon steel (S-C material).

SCM steel machines well and is generally easy to work with. The relatively low alloying element content keeps material costs lower than stainless steel and other heavily alloyed materials. The chromium content also forms a passive oxide layer that provides a degree of corrosion resistance.

• Good corrosion resistance

• Low cost

• Excellent mechanical strength

Types of SCM Steel

SCM steel grades are classified by their carbon and alloying element content. The digits following the "M" consist of a one-digit code representing the primary alloying element content and a two-digit number representing the carbon content (carbon percentage multiplied by 100).

• SCM415

• SCM418

• SCM420

• SCM425

• SCM430

• SCM432

• SCM435

• SCM440

• SCM445

• SCM822

Material Selection Notes

While SCM steel has corrosion resistance thanks to the passive oxide layer formed by its chromium content, the chromium level is much lower than in stainless steel, so it should not be expected to match stainless steel's corrosion resistance. If rust or corrosion is a concern for the application, a surface treatment such as plating will be necessary.

• Susceptible to rust

SCM Steel CNC Machining at Yumoto Electric

Yumoto Electric manufactures custom SCM machined parts starting from a single piece. We have experience with over 200 materials, including metals such as stainless steel, molybdenum, and titanium; and engineering plastics including PEEK, PPS, MC Nylon, and POM.

If you’re unsure about material selection or machining methods, we offer complimentary consultations to help optimize your design and production. For any questions, please feel free to contact us.