In 2014, the production and sales of automobiles were 23.722 million and 23,419,900, an increase of 7.26% and 6.86%. Among them, commercial vehicles produced and sold 3,803,100 units and 3,791,300 units, down 5.69% and 6.53% year-on-year. In 2014, sales of commercial vehicles of 37,913,24 vehicles accounted for only 16.14% of the total automotive market.
Among them, according to automobile fuel, diesel vehicles sold a total of 2,805,966 vehicles, gasoline vehicles sold a total of 899,970 vehicles, and other fuel vehicles sold a total of 85,388 vehicles, accounting for 74.01%, 23.74% and 2.25% of the total commercial vehicle sales in 2014, respectively.
According to the model, the truck sold a total of 3,184,406 vehicles in 2014 (2,436,493 vehicles sold, 468,923 vehicles for non-complete vehicles and 278,990 trucks for semi-trailer trucks); 606,918 vehicles were sold in total (529,548 vehicles sold, non-complete vehicle sales) 77,370 vehicles).
The cold working methods of steel pipes mainly include cold drawing and cold rolling. The raw materials of cold-rolled steel pipes can be hot-rolled seamless steel pipes or welded pipes. The common characteristics of the cold working method of steel pipes are high dimensional accuracy and good surface roughness. It can produce very thin (up to 0.05~0.01mm) thin-walled tubes and very thin (up to 0.3~0.1 mm in diameter) capillaries.
Generally, the production process of seamless Steel Pipe can be divided into cold rolling and hot rolling. The appearance of cold-rolled seamless steel pipe is shorter than that of hot-rolled seamless steel pipe. The wall thickness of cold-rolled seamless steel pipe is generally smaller than that of hot-rolled seamless steel pipe. But the surface looks brighter than that of thick wall seamless steel pipe. The surface is not too rough, and the diameter is not too much burr.
In order to obtain seamless pipes with smaller size and better quality, cold rolling, cold drawing or a combination of the two methods must be used.
High precision cold drawn precision steel pipe is a new type of steel pipe, which is mainly characterized by high precision. There are usually two production processes of two high mill and three high mill. The precision of three high mill in producing cold rolled seamless steel pipe is higher, which can be controlled within a few wires, but the price is relatively higher.
The product specification range of cold rolled steel pipe is: outer diameter 4.0 ~ 450mm; The wall thickness is 0.04 ~ 60mm. Compared with the cold drawing method, the advantage of the periodic cold rolling method is that the shrinkage of the pass surface is large, there is no need for difficult head, and the yield is high.
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Shandong Guanzhou Iron and Steel Group Co., Ltd. , https://www.guanzhouiron.com