Appendix B

Scope

MPIF Standard 35 is issued to provide the design and materials engineer with the information necessary for specifying those P/M materials which have been developed and accepted by the P/M parts manufacturing industry as standard and representative of their capabilities and commercial practices. It is reasonable to expect that any properly equipped and experienced P/M parts manufacturer could supply P/M materials that will meet this standard.

MPIF Standards are issued and adopted in the public interest. They are designed to eliminate misunderstandings between the manufacturer and the purchaser and to assist the purchaser in selecting and obtaining the proper material for his particular product. Existence of an MPIF Standard does not in any respect preclude any member or nonmember from manufacturing or selling products not included in this Standard.

A Standard of the Metal Powder Industries Federation defines a product, process or procedure with reference to one or more of the following: nomenclature, composition, construction, physical properties, mechanical properties, dimension, tolerances safety, operating characteristics, performance, quality, rating, testing, and the service for which designed.

The data provided herein represent typical mechanical properties achieved under conventional manufacturing procedures. Higher mechanical properties and other improvements in performance characteristics can be obtained by experienced P/M parts manufacturers through the use of more complex processing techniques or different starting materials.

By referring to the property and performance values specified in each of the P/M Materials Standards, it is possible for the user to designate the exact material he desires for a specific application. It should also be apparent that the range of properties available through powder metallurgy is constantly increasing and that there usually are several alternative approaches toward achieving identical properties and performance. The data given are realistic and can serve as an effective guideline in the proper application of the products of powder metallurgy.

Explanatory Notes

The following describe and explain the details of the P/M Materials Standards. An understanding of what is intended will aid the Standards user in the proper interpretation of the data furnished.

Material ...

A word description of the P/M material being specified.

Designation ...

A code designation of the P/M material being specified which is based on the P/M coding system adopted by the industry. The coding system offers a convenient means for designating the type of material, composition and density of a P/M part. It should be noted that those code designations shown in Standard 35 and revisions thereof apply only to P/M materials standardized by the Metal Powder Industries Federation.

Note: Materials not yet adopted as industry standards should not be classified under the MPIF coding system.

In the coding system the prefix letters denote the general type of material; for example, the letters "CT" = bronze.

The four digits following the prefix refer to the composition of the material

In nonferrous materials, the last two numbers in the four digit series designate the percentage of the major alloying constituent. If there are no minor constituents, two zeros are indicated for the first two digits. If a minor constituent is present, the first two numbers designate the percentage of the minor constituent. Additional minor constituents are indicated in the prefix letters only.

In ferrous materials, those major alloying elements (except carbon) which are shown as ranges are included in the prefix letter code. Other elements are excluded from the code but are represented in "Chemical Composition" (Line 1). The first two digits of the designation indicate the percentage of the major alloying constituent present.

Carbon content in ferrous materials is designated by the last two numbers in the four digit series. The carbon content up to and including 0.3% will be considered as zero, higher contents will be indicated in ranges and coded as follows:

The percentage of carbon that is metallurgically combined is to be indicated in the coding system. Free carbon such as graphite in certain bearings is not to be included in the coding but may be referred to elsewhere in the Standard.

In the case of P/M Stainless Steels the four digit series shall be replaced with the appropriate designation adopted by the American Iron and Steel institute, but the MPIF letter codes will still be used as part of the designation in this standard.

The suffix letter denotes the density range of the material. The range used is that in which the mean density lies.