一种新型齿柱在密闭PDC取心钻头上的应用

目前，PDC钻头有二种形式，即胎体式和钢体式。其制造工艺既复杂又不方便，在钻头冠部钻孔和制造石墨模具都需要特殊的加工设备，加工费用高。PDC钻头的制造之所以复杂是为了更好地提高钻头冠部端面的强度和抗冲蚀性能。取心钻头是一种特殊的PDC钻头，对其使用性能的要求没有全面钻进的严格。为了节约取心钻头的制造成本，将可焊性好的普通合金钢齿柱替代WC齿柱，直接将齿柱用普通电弧焊的办法牢固到钻头钢体上。用这种工艺做了4只密闭PDC取心钻头，经对比试验，其使用性能达到了国内同行业的先进水平，但制造成本却大大降低了。这种新齿柱和新工艺的应用，能使布齿灵活，操作简便易行，无需特别的加工工具，所带来的经济效益是巨大的。

A New Kind of Stub Apply to the Core Bit

At present,there are two kinds of bits,the matrix body and the steel-body drill bits. The manufacture processes are all very complicated,and need the special equipments to make graphite pattern.A lot of stub holes are also drilled on the top of bits,so the costs are very great. The core bits belong to special PDC bits,the performance needed are less than that of the drilling bits. In order to reduce the cost,the steel stubs are welded onto the steel body instead of the WC stubs. With the comparison of other bits,four bits manufactured by these methods can get excellent performance in China. But the costs are also reduced greatly. These new bits have flexible distribution of cutters and can make easier operation. No special instruments are needed,so the economic efficiency is very visible.