Although there are many types of tapping screws, they all have the following similarities:
Many customers who want to know, or are going to use polyacrylamide, will ask which molecular weight of polyacrylamide is good. I can only say that this is good. In fact, the molecular weight of polyacrylamide is not good or bad. The important thing is that it is not suitable. Suitable for your industry, for example, just like we go shopping in the mall, there are many beautiful things, but not all are suitable for ourselves, we have to choose the most suitable purchase for you, this is the purpose of shopping in the mall. At present, the polyacrylamide anion type on the market generally has a molecular weight of about 18 million, and the higher the molecular weight, the more expensive the price. Cationic polyacrylamide, molecular weight from 8 million to 12 million, the higher the ionicity, the more expensive the price, the ionicity is from 10-60. 
(1) are generally made of carbonized carbon steel (accounting for 99% of total production). It can also be made of stainless steel or non-ferrous metals.
(2) The product must be heat treated. Carbon steel tapping screws must be carbonized and stainless steel tapping screws must be solution hardened. In order to make tapping screws to meet the requirements of the standard of mechanical properties and performance.
(3) The product surface hardness is high, the core toughness is good. That is, "soft inside strong outside". This is a major feature of tapping Screw performance requirements. If the surface hardness is low, it can not be screwed into the matrix; If the core toughness is poor, a twist will break, can not be used. So "inside soft outside steel" is self-tapping screw to meet the use of performance, very important requirements.
(4) The surface of the product needs surface protection treatment, generally electroplating treatment. Some product surface must be treated by phosphate (photostatting), such as wall panel self - tapping screws for photostatting.
(5) Production by cold heading process. It is recommended to use high-speed cold heading machine and high-speed wire rolling machine or high-speed planetary wire rolling machine. High speed is emphasized here to ensure product quality. Only the head of tapping screw produced by high-speed machine is well formed and the thread quality is high.
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