The brake drum is a security piece that relates to the […]
The brake drum is a security piece that relates to the safety of people's lives and property, and it is also a consumable and consumable part. The market demand is particularly large. At present, the annual output in China is about 10 million or more. Because the product structure is relatively simple, machine modeling and manual modeling are easy to launch. Almost all parts of the country have production brake drums. The large-scale enterprises I have been to, the mechanized assembly line to produce brake drums, the annual output is about one million. I have also been to some small businesses with an annual output of tens of thousands.Brake drum There is also an industrial park like a town in Longyan County, Hebei Province. There are more than one hundred foundries in the production of automobile brake drums; the brake drum production in the entire area should be more than one million. However, brake drums produced by large companies are generally supplied to domestic axle factories or exported to foreign countries, while brake drums produced by small enterprises are mostly supplied to parts and aftermarket parts. The quality and credibility of its products are difficult to be accepted by the regular axle factory. According to the enterprises I have seen and learned, due to different product structure and different supply targets, the production process is different, but in general, the quality problem There are still many, can not meet the quality requirements of the brake drum for vehicles
Due to the good thermal conductivity, shock absorption, wear resistance, excellent casting properties and low manufacturing cost of gray cast iron, almost all of the brake drums of motor vehicles use gray cast iron parts, which are graded HT200 and HT250.
There is only one gray iron casting standard in China, which is JB/T9439-2010, and there is no special standard for gray iron castings for automobile brake drums. There is also no description of special gray cast iron in the machine. Only the American Society for Testing and Materials ASTMA 159-83 (reviewed in 1993) has specially developed standards for automotive gray iron castings. The brake drum has three cast iron grades according to its load capacity. At the same time, the quality requirements of the brake drum in the dynamic mechanical gray cast iron standard of the American Society of Automotive Engineers SAEJ431 are basically the same as ASTM A159-83. At present, most of China and foreign countries refer to the American brake drum standard. The factory standard is given on the drawings or the acceptance criteria. A standard level reflects the level of workmanship and quality, and a high level of standards can produce high quality products.