Core tip: in the development of technical specifications for MIM materials, the MIM Association of the same grade system and AISI-SAE. The use of these names is because the MIM parts are used to replace the corresponding products in the use of the corresponding forging. When a certain material is made with MIM process, it should be added "MIM"". For example, 316L stainless steel with MIM process can be represented by "MIM-316L".
American MPIF standard 35 - Standard for metal injection molding parts materials
18-35-03-88-1.pdf
1, MIM parts of the material standards of the notes and definitions
(1) named after MIM
In the formulation of the technical specification of MIM material, the MIM Association uses the same grade system and AISI-SAE. The use of these names is because the MIM parts are used to replace the corresponding products in the use of the corresponding forging. When a certain material is made with MIM process, it should be added "MIM"". For example, 316L stainless steel with MIM process can be represented by "MIM-316L".
Before choosing a specific material, careful analysis of the design and the end use of the parts is required, including dimensional tolerances, parts design and die design. In addition, MIM parts manufacturers and the buyer must agree on the final performance requirements of finished parts. The problems such as static and dynamic loads, wear resistance, cutting performance and corrosion resistance are also provided.
(2) some basic concepts and definitions
Minimum values of the concept of metal powder industry association for structural parts of the powder metallurgy materials using the concept of minimum mechanical properties. In the use of MIM technology to manufacture parts, the use of these values as a basis for the user to choose a specific application materials. In order to help users select materials, the standard values of other properties are listed in addition to the minimum mechanical properties. Thus, the user can choose and determine the appropriate MIM materials and the most suitable for the specific purpose of the performance. Provided the data provided for the minimum mechanical properties of the material, and in the industrial production conditions can be reached the standard mechanical properties. The mechanical properties and other properties can be improved by using a more complex process. To choose one of the best materials for both performance and price two, the user and the MIM parts manufacturers to discuss the use of the most important parts.
The minimum value of MIM for the lowest value of the material, for the sintered state and (or) heat treated state of all the materials are used in the yield strength (0.2% residual deformation method), the ultimate tensile strength and elongation. Because the density of MIM material is close to true density, so its performance is similar to that of forging and rolling.
In order to establish the standard, the tensile properties are determined by tensile test specimen, the tensile test specimen is a special preparation of MIM material for evaluating material (the MIM material sample of MPIF standard 50). The tensile properties of the samples prepared by mass production of parts or by non - standard MIM specimens may be different from that of the sample prepared in accordance with MPIF standard 50.
In the preparation of the technical specifications of the MIM material, the actual method of the minimum strength value is determined by the manufacturer.
And the use of production of the first batch of parts and mutually agreed on the part of the method, static or dynamic acceptance test. For example, according to a given part of the design, the agreed that the load must be greater than a given force. If in the acceptance test, it exceeds the specified value, it indicates that the minimum strength value is reached. Also the use of the first batch of parts in the use of the test showed that it is qualified. Static and dynamic fracture loads are measured separately, and the data are analyzed to determine the minimum breaking force of the mass production parts in the future. In the future the production of the parts as long as more than the minimum force, it shows that the intensity of the technical specifications. Can also be used to prove the strength of tensile specimen. These samples and parts should be made of the same material, and the material density of the parts is the same, and the production of parts with the sintering and heat treatment. However, the defects produced during the actual parts forming may limit the performance of tensile test specimens. In order to meet the minimum performance requirements, it may be necessary to add quality inspection of the parts, such as X ray analysis.
The use of MPIF standard 35 to develop the technical conditions for MIM material, means that unless the buyer and the manufacturer has another agreement, the material will have the minimum performance value in the standard. Of course, if the sample is used to determine the value, the sample should be determined by the manufacturer and the shape and other characteristics of this kind of material will be evaluated under the same conditions as in the same condition.
Standard values for each of the listed MIM material are corresponding to a set of properties (i.e., density, hardness, elongation, etc.) standard values, for a specific application, some or all of the performance may be very important. The standard values for the column density are determined by the interpolation method by the average mechanical properties and density curves. The mechanical properties data were derived from the "Circulation" of the specimen and the heat treatment.
List of criteria values are only for general guidance, and they are not considered to be minimum values. When used in general manufacturing process, the selection of parts of the test area or the use of specific manufacturing process will be slightly changed. For each type of material required by the buyer, the technical conditions must be used and the performance of the MIM parts manufacturer shall be fully discussed. For each of the MIM parts, except for the performance of the minimum value, the required performance values shall be based on their intended