NXF UNS S304/ 1.4301/SUS304/Z7CN18-09 304 Stainless Steel Grade Class8.8-12.9 Fastener Hexagon Flat Head Set Screw

1.Raw‑material screening and preparationHigh‑quality 304 stainless‑steel wire rods are selected as raw materials. Workers inspect metal surface condition, chemical composition and hardness index. The stainless‑steel bars go through wire‑drawing treatment to achieve precise‑diameter wire stock, removing oxide scale and surface burrs to guarantee stable follow‑up forming quality.

2.Cold‑heading formingThe treated steel wire is cut into fixed‑length blanks by automatic cutting‑off machines. Blanks are delivered to cold‑heading equipment for one‑shot cold forging. This procedure shapes the cylindrical blank body and stamps the inner‑hexagon driving recess at one end. Cold‑forged processing keeps intact the metal‑fiber structure and improves screw comprehensive hardness.

3.Thread rollingFormed workpieces enter the thread‑rolling station. Precision thread‑rolling dies extrude full‑length external threads. Compared with thread‑cutting methods, rolling processing generates dense thread surface, enhances thread tensile strength and makes threads smooth without sharp burrs for smooth assembly.

4.Flat‑end finishingOne end of each set‑screw is machined and polished into a smooth flat contact face. Strict flatness control ensures even stress contact when tightening, preventing component surface abrasion and slipping in locking work.

5.Deburring, cleaning and passivationAll work‑pieces remove residual burrs by vibration grinding. Ultrasonic washing washes away metal chips and machine oil. SS304 screws receive stainless‑steel passivation treatment to strengthen anti‑corrosion performance and avoid surface rust spots.

6.Quality inspection and finished‑product sortingInspectors test thread tolerance, hexagon‑hole dimension, surface finish and flat‑end flatness. Defective goods are screened‑out. Qualified set‑screws are sorted by specification, then packed for export shipment.