Aobo Steel Technical Tool

Steel Hardness Conversion Calculator for Tool Steel

Enter one hardness value and calculate the nearest equivalent values. Use the HRC range for hardened tool steel, and use the HRB range for annealed or softer steel. The calculator does not force values outside the valid table range into a result.

Hardened Tool Steel / HRC Range

Use this range for hardened and tempered tool steels, including D2, A2, O1, S7, H11, H13, M2, M35, and M42. Valid input ranges: HRC 20-68, HV 238-940, HBW 226-739, HBS 226-500.

Enter one value above. The calculator uses the last edited field as the input source.

Annealed or Soft Steel / HRB Range

Use this range for annealed, normalized, or softer steel where HRC is not suitable. This range is useful when reviewing MTC hardness values or soft supply hardness. Valid input ranges: HRB 55-100, HV 100-240, HBS 100-240.

Enter one value above. The calculator uses the last edited field as the input source.
The values are approximate equivalents, not exact conversions. Use them for comparison and communication. For inspection, acceptance, or MTC confirmation, test hardness by the method specified in the order or standard.

Which Range Should You Use?

Use the HRC range when the steel has been hardened and tempered. Use the HRB range when the steel is still soft, annealed, or normalized. This separation prevents low HB or HV values from being incorrectly matched to a hardened steel range.

HRC for hardened tool steel HRC is the common working hardness scale for hardened tool steel, such as D2 at 58-60 HRC, H13 at 44-52 HRC, or high-speed steel above 60 HRC.
HB and HRB for soft supply Annealed tool steel is usually checked by Brinell hardness. Many supply specifications and MTCs use values such as maximum 229 HB or maximum 255 HB.
HV for technical comparison HV is common in technical references, inspection reports, surface hardness checks, and heat-treatment data. It is useful for comparison, but it does not replace the required test method.

Data Source and Use Limit

The calculation data are simplified from ASTM E140 hardness conversion tables for non-austenitic steels. The HRC range is based on the Rockwell C hardness range table, and the HRB range is based on the Rockwell B hardness range table. For this tool steel calculator, only the practical front-end scales are retained: HRC, HRB, HV, HBS, and HBW.

Why the values are approximate

Rockwell, Brinell, and Vickers tests use different indenters, loads, indentation shapes, and measurement principles. A value such as 60 HRC can be compared with about 697 HV, but it is not a mathematical unit conversion like millimeters to inches.

Tool steel grade, carbide distribution, heat treatment condition, surface preparation, sample thickness, and testing equipment can all affect the reading. Use the converted value for quick comparison, not for final acceptance.

Aobo Steel Supply Note

Aobo Steel supplies tool steel round bar and plate mainly in annealed condition. Final hardening and tempering should be carried out by the customer or a qualified heat-treatment facility. For bulk tool steel supply, MTC requirements, and grade selection support, contact our sales team before ordering.

Need Tool Steel Supplied in Annealed Condition?

Aobo Steel supports bulk orders of tool steel round bar and plate, with MTC per order and practical grade selection support for distributors, stockists, and industrial buyers.

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