Comparison Between SCM440H and SCr420 Steel

08/12/2020

Are you using SCM440H steel? Have you heard of SCr420? Are you unsure which steel grade to choose between SCM440H and SCr420? If these questions resonate with you, this article will help clarify the differences and similarities to guide you toward selecting the most suitable alloy steel.

One of the most familiar steel grades at Sevit is SCM440H. It is widely used in plastic molds and transmission shafts due to its notable components, Chromium and Molybdenum, which enhance durability, wear resistance, and are broadly applied in machinery manufacturing.

However, aside from SCM440H, another alloy steel grade gaining attention is SCr420. For some, distinguishing these two steel billets can be challenging, and it might be unclear which to choose.

To better assist you in product development, Sevit provides this article, outlining the advantages, disadvantages, and applications of SCM440H and SCr420.

Comparison Between SCM440H and SCr420 Steel

Comparison Between SCM440H and SCr420 Steel

1. Differentiating SCM440H and SCr420

SCM440H

SCR420

- SCM440H is an alloy steel grade named per JIS standards of Japan.

- Classified by some manufacturers as Chromium-Molybdenum steel.

- SCr420 is a steel grade named per JIS standards of Japan.

- Contains mainly Chromium and is classified as low-alloy steel by some.

2. Detailed Chemical Composition Comparison Between SCM440H and SCr420

No.	Chemical Composition	SCM440H (%)	SCr420 (%)
1	C	0,38 - 0,43	0,17 - 0,23
2	Si	0,15 - 0,35	0,15 - 0,35
3	Mn	0,65 - 0,85	0,55 - 0,85
4	P	≤ 0,03	≤ 0,03
5	S	≤ 0,03	≤ 0,03
6	Cr	0,9 - 1,2	0,85 - 1,2
7	Mo	0,15 - 0,3	-

From the table above, the most notable differences are the Carbon and Molybdenum content:

- Carbon Content: SCM440H has significantly higher carbon content (0.38% - 0.43%) than SCr420 (0.17% - 0.23%), resulting in superior hardness and wear resistance.

- Molybdenum: SCM440H contains Molybdenum (absent in SCr420), enhancing wear resistance and providing a smoother surface finish.

Thép SCM440 và SCr420 khác nhau và giống nhau như thế nào?

3. Mechanical Properties: SCM440H vs SCr420

Mechanical Properties

SCM440H

SCr420

Deformation resistance and wear resistance

Excellent

Moderate

Load-bearing capacity

High

Moderate

Hardness after heat treatment

Up to 55 HRC

Tensile strength

~9.8 MPa

~8.3 MPa

Elongation

~16%

Welding capability

Moderate

Good

4. Applications of SCM440H and SCr420

SCM440H

SCr420

- Used for manufacturing gears, shafts, and components in automobile and motorcycle engines.

- Additionally, SCM440H is utilized for mold fabrication (plastic molds, rice husk molds, pellet press molds).

- High-strength anchor bolts (grade 8.8 or above) for hydropower projects and telecom stations.

- Rolling shafts and gears in production plant systems.

Used for manufacturing machine components or small parts (with cross-sections under 30 mm), such as transmission gears, gear shafts, CAMs, piston pins, and clutch sleeves.

Additionally, SCr420 is applied in valve bodies, pumps, and related accessories.

Utilized in welding applications within the mechanical engineering field.

Both SCM440H and SCr420 have their distinct strengths and weaknesses, which make them suitable for specific applications. Depending on your technical requirements, you can select the most appropriate material for your machining needs.

Contact Sevit:

* Tel: +84 332 91 61 61

* Email: sales@sevit.vn

* Zalo: Sevit Special Steel