The present invention discloses a manufacture method for a composite layer of a complex alloysteelpipe, a fastening element, and a protective grating.
本发明公开了一种多元合金钢管、紧固件、防护栏复合层的制作方法。
2
With the development of Sinopec and the increasing proportion of the Sulfur in petroleum, the demand of the alloysteelpipe used in Sinopec producing equipments is unceasingly increasing.
随着中石化原油加工量及原油含硫比例的不断提高，中石化生产装置用合金钢管的需求量不断加大。
3
Since 2011 carbon and alloysteel seamless pipes for synthesis of carbon steel pipe and outer pipe project of Inner Mongolia Donghua Energy Co., Ltd.