盾构滚刀材料表面镍基碳化钨涂层摩擦学性能研究

目的 盾构滚刀磨损是盾构施工中最常见的问题之一,为减缓刀具的剧烈磨损、延长刀具的使用寿命,采用等离子堆焊工艺在盾构滚刀表面制备镍基碳化钨涂层以强化滚刀性能,基于盾构滚刀服役的真实工况,研究滚刀涂层的摩擦学性能及其合理的评价方式.方法 对镍基碳化钨涂层在往复滑动、冲滑复合(冲击+滑动)两种相对运动模式下进行摩擦磨损试验研究.结果 制备镍基碳化钨涂层后可提高滚刀的耐磨性.往复滑动磨损后,镍基碳化钨涂层的磨痕宽度为0.42 mm,而H13钢的磨痕宽度达到0.78 mm,镍基碳化钨涂层的抗冲滑性能也明显优于H13钢.两种相对运动模式下镍基碳化钨涂层均主要承受磨粒磨损,但往复滑动模式下涂层存在局部剥落,而冲滑复合模式下则伴随一定的粘着磨损.结论在两种相对运动模式下,镍基碳化钨涂层表面的高硬度碳化钨颗粒都可阻止磨粒对较软镍基合金区域的切削与碰撞.相较往复滑动模式,冲滑复合模式下镍基碳化钨涂层要承受冲击和滑动的耦合作用,涂层的磨痕特征以及损伤形式都有明显的不同.采用冲滑复合运动模式的摩擦磨损试验能对盾构滚刀刀圈的摩擦学性能进行更全面、合理的研究及评价.

Tribological Properties of Ni-based WC Coating Prepared on Shield Disc Cutter Material Surface

Disc cutter wear is one of the most common problems in shield construction. The work aims to prepare Ni-based WC coating on the disc cutter surface by means of plasma transfer arc welding, and study the wear properties of the Ni-based WC coating and its reasonable evaluation method based on the actual working conditions of the shield disc cutter to reduce the severe abrasion and prolong the service life of the cutter. The friction and wear tests of Ni-based WC coating was conducted under two relative motion modes of reciprocating sliding and impact-sliding. The results indicated that the Ni-based WC coating prepared on the surface of shield disc cutter material could improve the wear resistance of shield disc cutter. After reciprocating sliding wear, the wear scar width of the Ni-based WC coating was 0.42 mm, while that of H13 steel was 0.78 mm. In addition, the impact-sliding wear property of Ni-based WC coating was better than that of H13 steel. Ni-based WC coating was mainly subject to abrasive wear under the two motion modes. For the reciprocating sliding mode, the coating showed local peeling, while there was adhesive wear under the impact-sliding mode. The high hardness WC particles on the Ni-based WC coating can prevent the abrasive particles from ploughing and impact with the Ni alloy under the two motion modes. Compared with the reciprocating sliding mode, the coating was subjected to the coupling effect of both impact and sliding in the impact-sliding mode, which resulted in significantly different wear features and damage forms. Thus, the wear test under impact-sliding mode can provide a more comprehensive and relevant study and evaluation on the tribological properties of the disc cutter ring.