According to the preliminary data released by the General Administration of Customs of China on December 10, in November 2010, the export volume of plastic products in China was 654,276 tons, and the cumulative volume of exports from January to November was 6,763,415 tons, which was an increase over the same period of 2009. 14.2%.
The data also showed that in November 2010, the primary shape of plastic imports was 2.14 million tons, and the cumulative imports from January to November were 21.66 million tons, a slight increase of 0.2% over the same period of 2009.
Although there are many types of tapping screws, they all have the following similarities:
(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.
Round head Tapping screw,hex tapping screw,flat head tapping screw,pan head tapping screw,truss head tapping screw
Shenzhen Lanejoy Technology Co.,LTD , https://www.szcoolingrack.com