<矿>石英( quartz的名词复数 );
During the process of drilling, sand and gravel strata are often encountered, in which there are a lot of quartzs that are very hard and rubbing with variable shapes and sizes, so steel grains and horniness alloy drilling are not fit for the strata.
在钻探生产中经常遇到砂卵石层,砂卵石层中石英含量高,坚硬,研磨性强,形状各异,大小不一,钢粒钻进和硬质合金钻进都不适用钻进砂卵石层;
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