What is the plate plane anisotropy index and how does it affect the stamping process?

After the sheet is rolled, its mechanical and physical properties are anisotropic in the plane of the plate.

This is called plate plane directivity (plate plane anisotropy).

The directivity of the plate plane is mainly manifested in mechanical properties.

The difference in different directions within the board surface, for example, when bending, the bending line of the bending part is perpendicular to the fiber direction of the sheet, the allowable ultimate deformation degree is greater, and when the bending line is parallel to the fiber direction, the allowable ultimate deformation degree is smaller. Another example is in the cylindrical deep-drawn part, due to the directivity of the plate plane, the mouth of the deep-drawn part is uneven, and the "lug" appears, and the more obvious the directionality, the greater the height of the "lug".

But in the representation of the plates.

Among the various indicators of mechanical properties, the influence of the plate thickness directivity coefficient on the stamping performance is more obvious, so the size of the plate plane directionality is generally measured by the average difference of the plate thickness directivity coefficient r in several directions δr, which is specified as.

Since the directivity of the plate plane is not good for the stamping deformation and the quality of the workpiece, the δR value of the plate should be reduced as much as possible in production.

Hope it helps.

Anisotropy makes the physical properties of the material different in different directions.

The various chemical bonds in a molecule are directional.

Add a flattening process, or a rib pressing.

Say a specific product, specific requirements, and the specific problems that arise are easy to analyze!

If there is a problem, we must first confirm the reasonableness of the product tolerance requirements, mold Zen imitation layout, knot slow branch structure and so on, and then analyze the specific reasons!

After the sheet metal is rolled, there will be anisotropy in the plate plane, that is, along different directions, its mechanical properties and physical properties are different, that is, the plate plane directionality, which is expressed by the plate plane anisotropy index δ. For example, after drawing, the mouth of the workpiece is uneven, and the phenomenon of "lug" appears. The larger the anisotropic system δ the plate plane, the more serious the "lug" phenomenon is, and the greater the tangent height after drawing.

Because δ will increase the consumption of stamping process (trimming process) and materials, and affect the quality of punching parts, we should try to reduce the δ in production.

Differences?? It should be:

Anisotropy: The degree of deformation is different in all directions.

--Including: 1. Plate thickness direction anisotropy: thickness anisotropy coefficient r

2. Plate in-plane directional anisotropy: the in-plane directional anisotropy coefficient δr of the plate is used as an important mechanical index when feeding, and its requirements have been compiled into the material grade standards, as long as the grade is selected in the stamping process, the corresponding range has been stipulated, and there is no need to explain it.

When the relative bending radius of the stamping part is relatively small, there is a requirement for the anisotropy coefficient δr in the plane of the material, and the most closely related to δr (except for the internal structure composition of the material) is the rolling direction of the wrench, so when such documents are arranged in the stamping process, it is necessary to point out the angle value of the part and the direction of the wrench rolling. The rolling direction is the uncoiling direction.

Plate thickness directivity coefficient.

In the crystallization of steel ingots and the appearance of fiber structure during plate rolling, the plasticity of the sheet will be different due to different directions, this phenomenon is called the plasticity of the sheet anisotropy. Anisotropy includes anisotropy in the thickness direction and in the plane of the plate. The anisotropy in the thickness direction is expressed by the plate thickness directivity coefficient r.

The higher the r-value, the less likely the sheet is to become thinner during deformation. It is the premise of analyzing the deformation degree of stamping parts, designing manufacturability and formulating process specifications. If the shape of the sheet is appropriate, not only the uneven distribution of deformation along the sheet can be significantly improved, but also the forming limit can also be increased, and the height of the lug can be reduced, and the trimming allowance can be reduced.

In addition, for some parts that are directly formed after blanking, if the exact shape and size of the sheet metal can be given, the number of mold trials and mold adjustments can be reduced, thereby shortening the production cycle and improving productivity.

The direction of binding and bending have a great influence, for example, the perpendicular direction of bending and binding will lead to fracture at the edge of the material, especially after heat treatment.

It is best to bend in a parallel direction to the binding direction.

What are the mechanical properties of the index? I suggest that you should read the stamping technology books in this regard, and I will briefly introduce a few items here:

1. Yield strength: the ability to resist plastic deformation.

2, tensile strength: the ability to resist tensile fracture, 3, elongation after breaking, 4, yield ratio: the ratio of 1 and 2, together with the 3 items is the plasticity of the material, the higher the 3 items, the lower the 4 items, the better the plasticity of the material.

5, n value, hardening index indicates the degree of the phenomenon that the yield strength increases with the increase of the degree of deformation during the plastic deformation of the material, the larger the value, the more stable the forming, the less wrinkling, and the better the drawing performance.

6. R value, thickness anisotropy coefficient, represents the ratio of the strain in the plane direction of the plate to the strain in the direction of the thickness, the larger the value, the lower the degree of thinning in the thickness direction of the plate in the elongation. The less likely it is to thinn and crack.

The above is a mandatory item for the board material to be guaranteed, in addition to some such as the Erickson value and so on, you need to read the book yourself,

The sycamore is more and drizzle, to dusk, bit by bit. This time, what a sad word!

Basic requirements for stamping materials:

The materials used in stamping should not only meet the technical requirements of product design, but also meet the requirements of stamping process. The basic requirements of the stamping process for materials are mainly:

1) It has good stamping and forming performance.

For the forming process, in order to facilitate the stamping deformation and the improvement of the quality of the workpiece, the material should have good stamping and forming performance. That is, the material should have: good plasticity, small yield ratio, high elastic modulus, large plate thickness directivity coefficient, and small plate plane directivity coefficient. 

For the separation process, only the material is required to have a certain plasticity, and there are no strict requirements for other properties of the material.

2) The thickness tolerance of the material should be in line with the national standard.

Because a certain mold gap is suitable for a certain thickness of materials, the material thickness tolerance is too large, which not only directly affects the quality of the workpiece, but also may lead to damage to the mold and punch.

3) It has a high surface quality.

The surface of the material should be smooth and flat, without delamination and mechanical damage, and free of rust spots, oxide scale and other attachments. The material with the best surface is not easy to break during stamping, not easy to scratch the mold, and the surface of the workpiece.