Screws may be used in many places in life, but how mu […]
Screws may be used in many places in life, but how much do you know about some common knowledge about screws? Zhang weigao bolt factory will tell you something.
First, about electroplating
Most screws produced by zhejiang weigao need electroplating, the main purpose of which are to resist corrosion and rust. Those not plated also needs blackening treatment, mainly for rust prevention. After screws are produced, most of them are made of iron and stainless steel. Common electroplating includes blue zinc, white zinc, color zinc, environmental protection zinc plating, nickel plating, black zinc, black coating, etc.
Second, about wires
General screw wires is divided into carbon steel and stainless steel, of which carbon steel is divided into low carbon steel, medium carbon steel, and high carbon steel. Zhejiang weigao has 1010A, 1018, 10B21, 45 steel and so on. The stainless steel is SUS201, stainless steel SUS304, stainless steel SUS776, stainless steel SUS316, stainless steel SUS404, etc.
Third, on the hardness level
The hardness grade in screws/bolts can be divided into more than 10 grades: 3.6, 4.6, 4.8, 5.6, 6.8, 8.8, 9.8, 10.9, 12.9, etc. Among them, screws or bolts of grade 8.8 and above are made of low carbon alloy steel or medium carbon steel and are heat treated (quenched and tempered), commonly known as high strength screws/bolts, while screws produced by zhejiang weigao are usually graded 4.8/6.8/8.8.