Divided according to material: steel test piles, test piles of cement, plastic test pile. Test piles are divided into carbon steel test piles and steel test piles.
按材质分：钢质测试桩、水泥测试桩、塑料测试桩。钢质测试桩又分为碳钢测试桩和不锈钢测试桩。
2
The present invention has the advantages of effective increasing of graphite in pile-up alloy, reduced carbon content in the base tissue, raised alloying degree and raised toughness.
The welding rod capable of forming pile-up welded graphite-steel metal consists of welding rod core of low-carbon steel and nickel or nickel-base alloy and coating outside the welding rod core.