Abstract:Aiming at the problem of low impact toughness of the impregnated diamond bit matrix, a method of adding stainless steel fiber net to the carcass to improve the impact toughness of the matrix is proposed. The impact toughness of matrix was tested at different combinations of the three variables: the placement, mesh and number of layers of the fiber net. It was obtained through experiments: (1)stainless steel fiber mesh can effectively improve the impact toughness of the matrix, and the X-axis placement position is better; (2)when the mesh number of the fiber web is the same, the impact toughness of the matrix decreases as the number of fiber mesh layers increases; (3)in the case of the same number of fiber net layers, the impact toughness of the matrix increases first and then decreases with the increase of the number of fiber net layers. With a single layer of 30 mesh net added, the impact toughness of the carcass reaches a maximum. Through the electron microscopy of the impact fracture and the mechanical analysis of the fiber net, the reasons for this law are explained, and the method of further optimizing the impact toughness of the matrix is proposed.

Abstract:In order to tackle the problems of fast wear and short life of impregnated diamond bit in abrasive formation, the WC was added to iron base prealloyed powders as matrix metal owing to the characteristics of high hardness, high wettability and good abrasion resistance of WC. The hardness, impact toughness and bending strength of the matrix sample with different WC contents were tested to find the influence law of the support metal WC on the matrix performance. The results show that with the gradual increase of WC contents, the hardness, the impact toughness and the bending strength of the matrix sample exhibit the same trend: increase first and then decrease. From the perspective of micro-structure and energy, the reason of this rule is analyzed. Finally，it is concluded that the matrix achieves the optimal performance when the sintering temperature is 830℃ and the WC content is 5%. In this case, the strength and abrasiveness of the matrix sample are the maximum.

Abstract:Based on the analysis on joint fracture of wire-line coring drill pipe, study was made on the heat treatment process for drill pipe joint. The surface treatments were improved, joint fracture significantly decreased with longer service life of drill pipe joint, higher exploration construction efficiency and downhole trouble prevention.