National foreword

This British Standard is the UK implementation of ISO 185:2020. It supersedes BS ISO 185:2019, which is withdrawn.

The UK participation in its preparation was entrusted to Technical Committee ISE/111, Steel Castings and Forgings.

A list of organizations represented on this committee can be obtained on request to its secretary.

This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application.

Compliance with a British Standard cannot confer immunity from legal obligations.

This British Standard was published under the authority of the Standards Policy and Strategy Committee on 30 June 2020.

Foreword

ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.

The procedures used to develop this document and those intended for its further maintenance are described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the different types of ISO documents should be noted. This document was drafted in accordance with the editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).

Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of any patent rights identified during the development of the document will be in the Introduction and/or on the ISO list of patent declarations received (see www.iso.org/patents).

Any trade name used in this document is information given for the convenience of users and does not constitute an endorsement.

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This document was prepared by Technical Committee ISO/TC 25, Cast irons and pig irons.

This fourth edition cancels and replaces the third edition (ISO 185:2019), of which it constitutes a minor revision. The changes to the previous edition are as follows:

Correction to typographical error for relevant wall thickness of ISO 185/JL/HBW235 in Table 2; corrected from “4” to “40”. As a result of this change, the year of publication of ISO 185 in Annex D, Table D.1, column 1, updated from 2019 to 2020 to conform with this new edition.
Symbols for Brinell hardness and relative hardness updated to H_B and H_R, respectively, in B.2 and Figure B.1.

Any feedback or questions on this document should be directed to the user’s national standards body. A complete listing of these bodies can be found at www.iso.org/members.html.

Introduction

This document deals with the classification of grey cast irons, subdivided into two groups:

materials specified by their tensile strength;
materials specified by their hardness.

It is also possible to specify grey cast irons by a combination of tensile strength and hardness.

NOTE This document does not cover technical delivery conditions for grey iron castings.

The properties of grey cast iron depend on the form and distribution of the graphite and on the structure of the matrix.

For many applications, tensile strength and hardness are not the only properties of interest to casting designers. Other mechanical or physical properties can be decisive for the use of grey iron. For example:

the thermal capacity and the thermal diffusivity for disc brakes;
the damping capacity for engine blocks or machine beds;
the thermocycle fatigue for exhaust manifolds or ingot moulds.

Therefore, Annex A provides additional information of interest to casting designers.

Furthermore:

Annex B contains additional information on the relationship between hardness and tensile strength;
Annex C contains additional information on the relationship between tensile strength, hardness and wall thickness of grey iron castings;
Annex D provides cross-references of ISO 185 grade designations to other standard grades of grey cast irons.

1 Scope

This document specifies the properties of unalloyed and low-alloyed grey cast irons used for castings that have been manufactured in sand moulds or in moulds with comparable thermal behaviour.

This document specifies the characterizing properties of grey cast irons by any of the following:

the tensile strength of cast samples;
if agreed by the manufacturer and the purchaser, the tensile strength of samples cut from a casting;
if agreed between the manufacturer and the purchaser, the hardness of the material determined on castings or on a cast-on knob.

If agreed by the manufacturer and the purchaser, the combination of tensile strength from option a) or option b) and plus hardness from option c) can be specified. Information on specifying a combination of tensile strength and hardness is given in Annex B.

This document specifies eight grades of grey cast iron according to tensile strength (see Table 1) and six grades of grey cast iron according to Brinell hardness (see Table 2).

This document does not apply to grey cast irons used for pipes and pipe fittings and continuous cast products.

This document does not cover technical delivery conditions for grey iron castings.

NOTE General information on the engineering properties of grey cast irons is provided in ISO/TR 10809‑1.

2 Normative references

3 Terms and definitions

4 Designation

5 Order information

6 Manufacture

7 Requirements

7.1 Mechanical properties

7.2 Tensile properties

7.3 Hardness properties

7.4 Graphite structure

8 Sampling

8.1 General

8.2 Types of samples

8.3 Samples for tensile test

8.4 Samples for hardness test

9 Test methods

9.1 Tensile test

9.2 Brinell hardness test

9.3 Graphite structure

9.4 Alternative test procedures

10 Retests

10.1 Need for retests

10.2 Test validity

10.3 Nonconforming test results

10.4 Heat treatment of samples and castings

Bibliography

BS ISO 185:2020

Grey cast irons. Classification

Current

Published:

30 Jun 2020