The properties of the materials used in stamping are closely related to the stamping production, which directly affect the stamping process design, the quality of stamping parts and the service life of products, and also affect the organization of balanced production and the production cost of stamping parts.

When choosing the material of stamping parts, not only the service performance should be considered, but also the stamping processing and subsequent process performance requirements should be met. The basic requirements for stamping process are as follows.

1. Good stamping performance.

For the forming process, such as stretching, bending, bad punching, convex hull, etc., the material should have good stamping performance, that is, good fracture resistance, good mold adhesion and formability, otherwise the product is prone to deformation, rupture and so on, resulting in difficulties in mold repair. For the separation procedure, the material is required to have a certain plasticity.

2. High surface quality.

The surface of the material should be smooth and smooth without defect damage. The material with good surface quality is not easy to break and scratch the mold, and the surface quality of the parts is also good.

3. Material thickness tolerance should be in line with national standards.

Because a certain die gap is only suitable for a certain thickness range of materials, if the material thickness tolerance is too large, not only directly affect the quality of the parts, but also may lead to waste products. In correction bending, shaping and other processes, it is possible to cause damage to the die or press due to excessive thickness deviation.

1. Common materials for stamping

The most commonly used materials in stamping production are metallic materials (including ferrous and non-ferrous metals), but sometimes non-metallic materials are also used. Among them, ferrous metals mainly include ordinary carbon structural steel, high quality carbon structural steel, alloy structural steel, carbon tool steel, stainless steel, electrical silicon steel, etc; non-ferrous metals mainly include pure copper, brass, bronze, aluminum, etc; non-metallic materials are paperboard, laminate, rubber board, plastic board, fiberboard and mica, etc.

The supply state of metal materials for stamping is generally the sheet and strip of various specifications. Sheet metal can be used in the production of Engineering die, strip (coil) used in the production of continuous die, can also be used in the production of Engineering die. The size of sheet metal is large, which can be used for stamping large-scale parts, and can also be used for stamping small and medium-sized parts by cutting the sheet metal into strips according to layout size. The strip material (also known as coil material) has a variety of specifications of width, the unfolding length can reach tens of meters, coil-like supply, suitable for automatic feeding of continuous die mass production.

The relevant manuals and standards can be consulted on the grades, specifications and properties of various materials.

2. Reasonable selection of stamping materials.

The selection of stamping materials should take into account the requirements of stamping parts, stamping process requirements and economy.

(1) reasonable selection according to the requirements of stamping parts.

The selected material should enable the stamping parts to work normally in the machine or part and have a certain service life. Therefore, according to the use conditions of stamping parts, the selected materials should meet the requirements of corresponding strength, stiffness, toughness, corrosion resistance and heat resistance.

(2) reasonable material selection according to stamping process requirements.

For any kind of stamping parts, the selected materials should be able to form the qualified products steadily according to the requirements of the stamping process, which is the most basic and important material selection requirements. For this reason, the following methods can be used to select materials reasonably.

(1) test. According to the past production experience and possible conditions, several sheets which can basically meet the requirements of the stamping parts are selected for trial blanking. Finally, one with no crack or wrinkle and low reject rate is selected. This method is more intuitive, but with greater blindness.

(2) analysis and comparison. Based on the analysis of stamping deformation properties, the maximum deformation degree during stamping is compared with the allowable limit deformation degree of sheet metal stamping forming properties, and the sheet metal suitable for the stamping process requirements of this kind of parts is selected.

In addition, the same brand or the same thickness of the plate, and cold rolling and hot rolling points. In the domestic plate, the thick plate (t > 4mm) is hot rolled plate and the thin plate (t < 4mm) is cold rolled plate (also hot rolled plate). Compared with hot-rolled plate, cold rolled plate is of precise size and small deviation.

The surface defects are few, bright, the inner structure is compact, and the stamping performance is better. (Note: t generally represents the thickness of the die, such as the thickness of the template, the thickness of the material can be expressed by T. )

(3) reasonable selection according to economic requirements.

Selected materials should meet the use of performance and stamping process requirements under the premise, as low as possible, convenient source, good economy, in order to reduce the cost of stamping parts.