Stainless Steel Spring Materials | Sumida Shoji Co., Ltd.

Sumida Shoji Co., Ltd. is a pioneer in precision thin stainless steel spring materials.
We handle materials including the representative "Stainless Steel" SUS304 (18Cr-8Ni). We are committed to "Sincere Response," "Peace of Mind," and "Stable Quality." We execute every single task with "Awareness," "Pride," and "Responsibility." We aim to be a company that always remains helpful to our clients, now and forever.

News & Topics
Oct 1, 2026	Our website has been renewed. Thank you for your continued support. NEW There are no changes to the URL of each page. The site remains accessible via the conventional URLs. Additionally, the following two sections have been updated: Useful TipsGALLERY2 and Calculation FormulasGALLERY3> "If this page doesn't display properly, please clear your browser cache. Please ensure only 'Cached images and files' is checked, and uncheck all other options." Useful TipsGALLERY2
Oct 8, 2026	We have started handling "SR2 Width 980mm" manufactured by NIPPON STEEL CORPORATION. NEW For further details, please contact our sales representative. Thank you. Company Name: Sumida Shoji Co., Ltd Postal Code: 350-0833 Address: 1-103-24 Yoshinodai, Kawagoe, Saitama, Japan Phone: +81-49-227-5210 Email: sales-info@sumida-s.co.jp

One-Day Service

An explanation of steel grades, finishes, and hardness types.

Inventory & Thickness Tolerance Chart

An overview of representative inventory items available at Sumida Shoji Co., Ltd..

Sumida QC Process Chart

A brief summary and explanation of our Quality Control (QC) process contents.

• Stainless steel (SUS304, SUS301) spring plates (tX320X1000) are available for purchase starting from a single piece.
　　　(We stock 1/2H, 3/4H, and H materials.)

• Regarding hardness (HV), please verify via "Sumida Leaflet 1."

　(e.g.) JIS G4313 Hardness (HV) (HV: Vickers Hardness Symbol [JIS Z 2244])
　　　　SUS304-CSP → [ 1/2H: HV 250 or higher ] [ 3/4H: HV 310 or higher ] [ H: HV 370 or higher ]
　　　　SUS301-CSP → [ 1/2H: HV 310 or higher ] [ 3/4H: HV 370 or higher ] [ H: HV 430 or higher ] [ EH: HV 490 or higher ]
　　　　SUS631-CSP → [ 1/2H: HV 350 or higher ] [ 3/4H: HV 400 or higher ] [ H: HV 450 or higher ]

Update History
Oct 9, 2026	We have started handling "SR2 Width 980mm" manufactured by NIPPON STEEL CORPORATION. NEW For further details, please contact our sales representative. Thank you. Phone: +81-49-227-5210 Email: sales-info@sumida-s.co.jp
Oct 1, 2026	Our website has been renewed. Thank you for your continued support. NEW There are no changes to the URL of each page. The site remains accessible via the conventional URLs. Additionally, the following two sections have been updated: Useful TipsGALLERY2 and Calculation FormulasGALLERY3> "If this page doesn't display properly, please clear your browser cache. Please ensure only 'Cached images and files' is checked, and uncheck all other options." Useful TipsGALLERY2