本规范涵盖了适用于按英寸/磅尺寸订购的铝合金和镁合金挤压棒材、棒材、线材、型材和管材的既定制造公差。某些形状可能需要大于标准的公差；对其他人来说，公差可能比标准更接近。然而，除非买方和卖方另有约定，否则此处所示公差适用，并适用于所有回火，除非另有说明。

This specification covers established manufacturing tolerances applicable to aluminum alloy and magnesium alloy extruded bar, rod, wire, shapes, and tubing ordered to inch/pound dimensions. Tolerances greater than standard may be necessary for some shapes; tolerances closer than standard may be possible for others. Tolerances shown here, however, apply unless otherwise agreed upon by purchaser and vendor and apply to all tempers, unless otherwise noted.