May tatlong pangunahing materyales para sa grade 12.9 bolts (12.9 wedge anchor, 12.9 through bolt): carbon steel wedge anchor, stainless steel wedge anchor, at tanso. (1) Carbon steel (tulad ng carbon steel Wedge Anchor Bolts). Nakikilala namin ang mababang carbon steel, medium carbon steel, high carbon steel at ...
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