304 stainless steel large flat head self-tapping screw pan head umbrella head self-tapping screw cross pointed tail screw 3/4

The front wall sound insulation pad is used to absorb the heat and noise transmitted by the firewall, and also plays the role of heat insulation and vibration isolation, ensuring a relatively quiet and comfortable environment in the car and improving ride comfort. As shown in FIGS. 1 and 2 , the front wall sound insulation and heat insulation pad 101 is generally fixed to the vehicle body by means of screw buckles 102 . The screws 100 are clamped by the clamping feet 103 in the screw The limiting rib 104 clamps the screw 100. After the screw 100 is clamped into the screw buckle 102, the tail end of the screw 100 is exposed, which is easy to scratch the operator when assembling other components, and the exposed screw 100 is easy to cause corrosion, thereby affecting the connection strength of the screw 100, and also The service life of the screw 107 is reduced.

High-strength fastener materials mainly include ML35, 35K, ML40Cr, ML35CrMo steel, etc., of which 75ML35CrMo steel is imported. The main problems of the material are box segregation, decarburization, cracks and so on. The material needs to be spheroidized and annealed before cold forming, and the annealing is carried out in an oil furnace. There is no protective atmosphere in the furnace, and there is a decarburization phenomenon. 1.2 The high-strength fasteners, mainly grade 12.9, are quenched and tempered on the chain casting furnace production line. The temperature and atmosphere in the furnace are controlled by computer, and Rx gas is used as a protective atmosphere. Heating and anti-oxidation and decarburization can be effectively controlled, and the quality of the fasteners is intact during the heating process. The high-strength fasteners mainly of grade 8.8 are quenched and tempered on the vibrating hearth furnace. Affected by the structure of the vibrating hearth furnace, the sealing performance of the furnace is poor, the Rx atmosphere is not easy to control, the temperature difference of the furnace is large, and the parts are heated in the furnace. The collision and the length of time are inconsistent, and the quality of the fasteners during the heating process is poor, and there are phenomena such as decarburization, bumps, and uneven heating.

Pre-embedded copper nuts with straight pattern/twill pattern/herringbone embossing and other various anti-skid patterns can be completed at one time by automatic lathes. More complex copper nuts are processed by forming knives and table turning/tapping. Many products processed after machining are relatively simple reticulated copper nuts and straight-grained copper nuts, which are made of C3604 easy-turning brass. The surface pattern is directly drawn from the original bar, and the pattern is full and the tooth peak and bottom are clearly visible. Injection molding into plastic parts Afterwards, it can bear more high torque.

The more complex inlaid embedded copper nut copper insert nut specification is M8, this copper insert nut is embedded in the injection molded part of the car, 5 twill embossing, 4 left twill embossing, 1 right twill embossing Knurling. Since there are multiple rolling patterns, double tool rests + double embossing rests are used, and 5 grooves and 2 chamfers are inserted at one time by a widening forming knife. The hot-pressed copper insert nut contains Reticulated and straight lines, the outer circle is conical, in the process of hot pressing to facilitate smooth introduction into the plastic hole.

The above content is uploaded by Yueluo or the Internet. If there is any copyright issue, please contact [email protected].