This specification covers tool steel compositions appropriate for usable shapes cast by pouring directly into suitable molds and for master heats for remelting and casting. Grades of the tool steel covered in this specification include air- and oil-hardening grades such as CA-2, CD-2, CD-5, CM-2, CS-5, CS-7, CH-12, CH-13, and CO-1. The steel shall be made by one or more of the following processes: electric-arc furnace or induction furnace and may be argon-oxygen decarburization refined. Each of the steel shall undergo chemical analysis and shall conform to the chemical composition specification for carbon, manganese, silicon, sulfur, phosphorus, chromium, molybdenum, vanadium, cobalt, tungsten, and nickel. Material shall be packed and marked with heat or lot number, specification number, steel type, and form to ensure safe delivery and proper identification.

1.1 This specification covers tool steel castings having chemical compositions similar to those of the standard wrought grades.

1.2 Several grades are covered and are designated by chemical composition shown in Table 1.

Composition, %

Grade

CS-7

CH-12

CH-13

CD-51

Element

UNS

T91907

Carbon

0.45–0.55

0.30–0.40

0.30–0.42

0.85–1.00

Manganese

0.40–0.80

0.75 max

0.75 max

1.00–1.30

Silicon

0.60–1.00

1.50 max

1.50 max

1.50 max

Sulfur

0.03 max

0.03 max

0.03 max

0.03 max

Phosphorus

0.03 max

0.03 max

0.03 max

0.03 max

Chromium

3.00–3.50

4.75–5.75

4.75–5.75

0.40–1.00

Molybdenum

1.20–1.60

1.25–1.75

1.25–1.75

...

Vanadium

...

0.20–0.50

0.75–1.20

0.30 max

Cobalt

...

...

...

...

Tungsten

...

1.00–1.70

...

0.40–0.60

Nickel

...

...

...

...

1.3 The values stated in either SI units or inch-pound units are to be regarded separately as standard. Within the text, the SI units are shown in brackets. The values stated in each system are not necessarily exact equivalents; therefore, to ensure conformance with the standard, each system shall be used independently of the other, and values from the two systems shall not be combined. Inch-pound units are applicable to material ordered to Specification A597 and SI units for material ordered to A597M.

1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.