What are the materials of screws? Some people may say, 'I don't work for a screw manufacturer, nor do I often negotiate with them for purchases. How could I possibly know the material of the screws?'? Next, Screw Girl will introduce the material of screws to everyone.
1. Accumulation hardening: Therefore, it is used for high-strength, corrosion-resistant screws. 17-4P
H. PH15-7Mo may achieve higher strength than the typical 18-8 type. Screw customization, such as size inspection items, specifies the thread gauge, thread stop gauge, thread small diameter, opposite edge width, diagonal dimension, nut height, and the perpendicularity of the nut support surface to the thread axis for hex nuts; The specifications for flat washers include inner diameter, outer diameter, thickness, coaxiality of the outer circle to the inner hole, and flatness. The mechanical performance inspection items for hexagonal nuts are specified as hardness and tensile strength; And only the hardness is specified for flat washers. Non standard screw customization inspection method: The inspection method for standard fasteners is specified in the technical specifications of the product. And professional standards have been established for the testing methods of fasteners (size and geometric accuracy).
2. Martensite: with a hardness of 35-45HRC, it has good machining performance, and 410 and 416 types may be strengthened by heat treatment. Non standard screws are divided into three main parts: size, mechanical properties, and surface defects. The specific inspection items for each section have different regulations based on different products. Heat resistant and corrosion-resistant screws for individual use. The easily machinable 420 type and 416 type have slightly higher sulfur content. The mechanical performance improvement with a sulfur content of R0.15% may enhance the maximum hardness value through heat treatment, and 53-58HRC is used for screws that require higher strength.
3. The representative grade of austenite is chromium nickel austenite with chromium content of about 18% and nickel content of about 8%. The most basic alloying elements of austenite are chromium and nickel. The element ratio commonly referred to as 18-8 chromium to nickel basically ensures that the structure of the steel is a solid austenite.
After reading the above content, do friends who are not sure about the material of screws understand. We may also proudly say that even if we haven't worked at a screw manufacturer or frequently negotiated with them, we still understand the material of screws.
