What is steel plate unevenness? How to measure?

2020年3月23日关作者 powerson metal

In the steel sheet trade, often encounter unevenness-related quality problems. Because of its complex standards, testing requirements are relatively special, many people may not understand.

1. What is unevenness?

Unevenness: The unevenness of the steel plate refers to the maximum distance between the surface and the platform measured by the steel plate, which contains the three types:medium waves, side waves and warping.

2. how to measure unevenness?

According to the explanation of unevenness, the most standard way to measure unevenness is: the specimen should be placed on a platform large enough, the specimen should not extend out of the platform. Then lift one end of the specimen and lower it, measuring maximum wave height (h) and wave length (L) with a standard gage with accuracy of mm

However, in many cases in the field we can not find a suitable platform to place the samples. In this case, we need to change the industry recognition, but not indicated in the standard method to make the initial judgment.

3. Standard requirements for unevenness?

Because of different products and different implementation standards, there are different requirements, q/BQB 401-2018 standard requirements as an example:

The unevenness of the steel plate refers to the maximum distance between the surface and the platform measured by the plate that is freely placed on the platform.

For steel plates with a minimum yield strength of less than 260MPa, if the user has special requirements for unevenness accuracy, it can also be ordered with superior precision according to sheet 2. If the user has special requirements for the L-suppheic produced by volume delivery, it may be agreed separately. Steel plates: not longer than 2000mm, the length of the steel plate is measured for unevenness. Plates longer than 2000mm can be intercepted at any 2000mm for unevenness measurement.

For steel plates with a specified minimum yield strength of less than 260MPa, when supplied with advanced unevenness accuracy or ultra-high unevenness accuracy, it is necessary to inspect the Edge wave in the case of arbitration, and the side wave should comply with the following provisions: When the length of the edge wave is not less than 200mm, for steel plates with a nominal width of less than 1500mm The wave height should be less than 1% of the length of the wave on the edge. When the length of the edge wave is not less than 200mm, the wave height should be less than 1.5% of the length of the side wave for steel plates with a nominal width of not less than 1500mm. When the length of the side wave is less than 200mm, the wave height should be no greater than 2mm.

In the subsequent processing of trade steel plate will cause unevenness exceeds the standard, such as cutting, laser cutting, lifting, packaging and other links will have an impact, and the customer processing parts will also create an impact.

In the processing use, even if the original plate unevenness accuracy is very high, but after using multiple processing processes, unevenness has produced changes, such as non-orientation electrical steel to do transformers, some need to punch holes after the multi-process and then stack. In this case, because of mold and other reasons caused by poor unevenness of parts, can not meet the requirements of stacking.

Therefore, to understand the actual use of customers needs, according to customer demand and steel mills signed different quality requirements, guaranteed quality of delivery steel plate.

分类目录steel