SPI has one concern—getting the customer's job produced perfectly and delivered on time.


Sometimes the most economical—and smartest—way to produce a part is to start from plate then transform it into the finished product. When specifications require stainless steel plate, doesn't it make sense to buy from a company that has specialized in supplying products from stainless steel plate for decades?

Stainless steel is used primarily when corrosion or oxidation is a problem. The features that it delivers cannot be duplicated by other materials at a comparative cost. Over 50 years ago, it was discovered that a minimum of 12% chromium would impart corrosion and oxidation resistance to steel. The term stainless steel was given to those ferrous alloys that contain a minimum of 12% chromium for corrosion resistance. This development was the start of a family of alloys which has enabled the advancement and growth of chemical processing and power generating systems upon which our technological society is based.

Subsequently several important sub-categories of stainless steels have been developed. The sub-categories are austenitic, martensitic, ferritic, duplex, precipitation hardening and super alloys.

Stainless Steel Plate Surcharges

August 2023 to February 2024

February 2024 Surcharges

304 / 304L – $0.8989
316 / 316L – $1.4035
410 – $0.3246
2205 Duplex – $1.3797
321 – $0.9498


Stainless Steel Grades & Reference Charts

SAE International, as a standards organization, maintains several alloy numbering systems, one of which, for steel grades, is the SAE steel grades system.

Today, steel quotes and certifications commonly make reference to both SAE and AISI, not always with precise differentiation. For example, in the alloy/grade field, a cert might say "304L", "AISI 304L", or "SAE 304L", and in most light-industrial applications any of the above is accepted as adequate, and considered equivalent, for the job at hand, as long as the specific specification called out by the designer (for example, "304L plate per ASTM-A240" or "304L plate per AMS 5511") is certified to on the certificate. The alloy number is simply a general classifier, whereas it is the specification itself that narrows down the steel to a very specific standard.

The SAE steel grade system's correspondence to other alloy numbering systems, such as the ASTM-SAE unified numbering system (UNS), can be seen in cross-referencing tables (including the ones linked below). For a listing of the grades in stock at Stainless Processing Inc., please refer to our inventory listing.

Stainless Steel Physical & Chemical Properties

Hot Rolled Annealed and Pickled Plate Specifications

Plate Flange Reference

A large portion of the products manufactured by SPI are flanges utilized in a variety of industries. Every flange specification is unique and Stainless Processing Inc specializes in fabricating them with precision from stainless steel plate. There are several categories of flanges including pipe, tube and blind and SPI has developed reference guides to help our customers with project management and ordering.

CLICK HERE to request our Stainless Processing, Inc. Plate Flange Reference Guide (includes AWWA Flanges).




Specifications for CAD and CAM File Submission

In most cases a drawing is not required but Stainless Processing, Inc is adept at helping out customers through each stage of the process and the process always begins with a design. We accept CAD, CAM and PDF files of your part drawings and can assist with the development of a drawing when you call (800)345-8126.

We are standing by to help! Submit your question through our online form or call (800)345-8126 to talk to an SPI stainless expert.


Not Sure Where to Start? Call (800)345-8126 or, Contact Us

Stainless Processing, Inc.
Stainless Processing, Inc.
200 Waverly Blvd., Coatesville, PA 19320
Phone: (800)345-8126 ■ (610)384-1278

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