它是个上端为钻杆母扣或者由壬，下端为套管公扣，内空心的转换接头。
Its upper end is drill pipe box or union, the nether end is casing pin. It is a crossover with hollow inside.
螺旋钻头底部阀门防止钻进过程中钻屑进入到空心的混凝土管中，当钻杆提出同时混凝土浆注入时，钻杆底部的阀门将被打开。
The valve at the bottom of auger can prevent drilling bits entering hollow pipe during operation. When drilling pipe is taken out and concrete grout is injected, the valve will be opened.
普通元钢或普通钢管经此轧机后，可直接变成实心或空心麻花钻杆钢。
Common round steel or steel tube may be rolled into solid or hollow twist drill rods by using the said rolling mill.
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