大型煤矿水力充填用的注砂管原先采用高锰钢管,后改用我厂专门生产的双层复合铸铁管。这种管外层为灰口铁,内层为白口铁,具有寿命长、价格低的特点,每年可为煤矿节约四百多万元。但此种产品的特点是分量重,井下作业相当困难。随着煤矿生产的发展,开采部位加深,要求注砂管能够承受更高的内压。 Large-scale coal mines with hydraulic filling of the original high-manganese steel pipe, then switch to my factory specializing in the production of double-composite cast iron pipe. This tube is gray iron outer layer, the inner layer of white iron, with long life, low prices, the annual savings for the coal mine more than 400 million. However, this product is characterized by heavy weight, downhole operations are quite difficult. With the development of coal production, mining sites deepen, requiring sand injection pipe to withstand higher internal pressure.