③ vanadium steel V, Ti Ti, Al Al, boron B, rare earth RE alloying elements are micro-alloying elements sunshine locking locking screw, although very low levels, should bid out in steel. For example 20MnVB steel. 0.07-0.12% of vanadium, 0.001 to 0.005% boron. ④ High quality steel in the steel should finally add "A" Zaozhuang locking locking screw, as distinct from the general high quality steel. ⑤ special purpose alloy structural steel, and steel dubbed (or suffix) represents the symbol of the steel use. For example Tai'an locking locking screw, riveting Lo 30CrMnSi special steel, steel, said as ML30CrMnSi. JB / T 4213-1996 fasteners cold heading die technical conditions Beijing Institute of Electrical and JB / T 7384.13-1994 fasteners self-tapping locking screw a circumscribed circle diameter gauge JB / T 7384.14-1994 wood screw threaded fastener trails caliper JB / T 7384.2-1994 fasteners countersunk head and countersunk head height test mode JB / T thickness test mode JB 7384.3-1994 fastener head and grooved support surface height between the / T 7384.4-1994 fastening member wrenching height test mode JB / T 7384.7-1994 Fasteners slot width plug JB / T 7384.8-1994 slotted fastener depth plug gauge 304 stainless steel self drilling screws, 304 stainless steel hose clamps Weifang locking locking screw Jinan Road ground (certified), locking the locking screw is provided by Jinan Daoqin Trading Company. Jinan Daoqin Trading Company (www.daoqinshangmao.com) (www.daoqinshangmao.com) Shandong Jinan, hardware accessories leader over the years, the company implement the scientific management, innovation and development, the principle of honesty and trustworthiness, and satisfy customer demand. Jinan Road ground in leadership with the staff warmly welcome all inquiries negotiations to create the Jinan Daoqin better future.