一字形钎头应予淘汰

CHISEL BITS BE ABOLISHED

锥体连接一字形钎头，主要用在单轴抗压强度σｄ ≤１５０ Ｍ Ｐａ 的非磨蚀性完整岩石中钻凿直径 Φ３８ ～Φ４２ ｍ ｍ 、深度≤３ ｍ 的眼孔．在破碎或坚硬的强磨蚀性岩石中，由于破岩效率低和几何形状稳定性差，导致眼孔不圆，钻速慢，寿命短，修磨频繁，重磨费用高，合金利用率低，机械故障和辅助工时增加，工人劳动条件恶化．因此，瑞典 Ｓｅｃｏｒｏｃ ， Ｓａｎｄｖｉｋ 公司的产品目录中，从７０ 年代中期开始，就用锥体连接的十字和球齿钎头取代了一字形钎头．现在，我们建议用更具优势的复合片齿钎头（ 例如 Φ３８ － ３ Ｐ１ Ｃ，Φ４０ － ４ Ｐ１ Ｃ，Φ４２ － ４ Ｐ１ Ｃ，Φ４２ － ４ Ｐ２ Ｃ 钎头） ，逐步更新目前广泛使用的一字形钎头．新系列钎头寿命为传统一字、球齿钎头寿命的２～４ 倍，而价格仅比同直径一字、球齿钎头高１／５

The chisel bits is mainly used to drill the non_abrasion complete rock whose single_axial compression strength is σ d≤150?MPa. The resulting drilled hole is Φ 36- Φ 42?mm in diameter and ≤3?m deep. When these chisel bits are used to drill the broken or strongly abrasion_resisted rock, the efficiency in rock breakage is low and the stability of the resulting geometrical shape is poor, resulting in the imperfectly_round hole, slow drilling speed, short service life, frequent polishing job, high regrinding cost, low rate in the efficient use of cemented carbides, the increase in the mechanical failure and auxiliary work time and the worsening labor condition. These disadvantages prompted the Sweden Secoroc and Sandvik Company to substitute pyramid_set cross bits and button bits for the chisel bits in the middle of 1970s. It is suggested that bit users should gradually substitute the insert_and_button complex bits such as Φ 38_3P1C, Φ 40_4P1C, Φ 42_4P1C and Φ 42_4P2C bits for the chisel bits now widely used. On the condition that the diameters of the bits under comparison are the same, the service life of the new series of insert_and_button complex bits is two to four times as long as that of the traditional chisel or button bits, but the price of the former is only 1/5 to 1/3 higher than that of the latter.