Selecting the material to be used from various materials is a work restricted by many factors. Therefore, how to choose the material of the part is an important part of the part design. The principle of selecting materials for mechanical parts is: that the required materials should meet the requirements of the parts and have good manufacturability and economy.

1. Usage requirements

The requirements for the use of mechanical parts are shown in the following points:

• The working condition and loading of the part; requirements to avoid failure modes.

The working condition refers to the environmental characteristics, working temperature, and the parts’ degree of friction and wear. For example, the materials should have good rust and corrosion resistance for parts that work in hot and humid environments or corrosive media. In this case, stainless steel, copper alloys, etc., can be considered first.

The influence of working temperature on material selection is mainly in two aspects: you need to consider that the linear expansion coefficients of the two parts that are matched with each other should not be too different to avoid excessive thermal stress or loosening of the fit when the temperature changes; you must also consider the case where the mechanical properties of a material change with temperature. For example, to improve the surface hardness of parts that work under sliding friction to enhance wear resistance, you should choose hardened steel, carburized steel, nitrided steel suitable for surface treatment, or good anti-friction wear-resistant properties.

• Restrictions on part size and mass.

The size and quality of the parts are related to the Variety of materials and the manufacturing method of the blank. When producing cast blanks, it is generally not limited by size and quality; when producing forged blanks, attention should be paid to the production capacity of forging machinery and equipment. In addition, the size and mass of the parts are also related to the strength-to-weight ratio of the material. Materials with a large strength-to-weight ratio should be selected as much as possible to reduce the size and quality of the parts.

• The importance of parts in the whole machine and components.
• Other special requirements (insulation, anti-magnetic, etc.) are required.

2.Process requirements

• To make parts easy to machine and manufacture, you should consider the complexity of the part structure, size, and stock type when selecting materials.
• For parts with complex shapes and large sizes, you should choose materials with good casting properties if casting billets are considered.
• If you consider welding stock, you should choose mild steel with good weldability.
• You should choose materials with better plasticity for parts with simple shapes, small sizes, large batches, and suitable for stamping and die forging.
• The material should have good heat treatment properties for parts requiring heat treatment. In addition, you should also consider the machinability of the material itself and the machinability after heat treatment.

3.Cost requirement

• The price of the material itself

Under the premise of meeting the requirements of use, we recommend that you choose materials with low prices. This is especially important for high-volume manufactured parts.

• The processing cost of materials

When the quality of the part is not large and the processing volume is large, the processing cost will account for a large proportion of the part’s total cost. Although cast iron is cheaper than steel, for some box-like parts produced in one piece or small batches, it is more expensive to use cast iron than steel to weld because the latter can save the cost of mold manufacturing.

• Material saving

Use heat treatment or surface strengthening (shot peening, rolling, etc.) process to give full play to and utilize the potential mechanical properties of materials; surface coating (chrome plating, copper plating, blackening, blue, etc.) methods can also be used to reduce corrosion and wear. To extend the service life of the parts.

Finally, if you still have questions about your part material selection, please get in touch with us, submit a free project consultation, and we will recommend suitable material options to you within 12 hours.

• Material utilization

Using no cutting or less cutting, such as die forging, precision casting, stamping, etc., can improve the utilization rate of materials and reduce the person-hours of cutting.

• Save valuable materials

By adopting the combined structure, expensive materials can be saved. For example, the worm gear ring of the combined structure is made of tin bronze with good anti-friction but is expensive, and the wheel core is made of cheap cast iron.

• Save rare materials

In this respect, the rich MN-B series alloy steel can replace the chromium-nickel series alloy steel, and the aluminum bronze can be used to replace the tin bronze in China.

• Material availability

When selecting materials, you should choose materials that are locally available and easy to supply to reduce the cost of procurement, transportation, and storage; for parts produced in small batches, you should minimize the variety and specifications of materials used on the same machine. to simplify provisioning and management.

Finally, if you still have questions about your part material selection, please contact us, submit a free project consultation, and we will recommend suitable material options to you within 12 hours.