1.1 该分类将机制耐火砖分为铬、铬镁、镁铬和镁砖（参见 3.1 ). 它不包括由电熔氧化镁制成的产品或由熔铸制成的产品。其目的是描述除铬砖外，通过氧化镁（MgO）含量的明显差异区分的类别。 1.2 本标准并不旨在解决与其使用相关的所有安全问题（如有）。本标准的使用者有责任在使用前制定适当的安全、健康和环境实践，并确定监管限制的适用性。 1.3 本国际标准是根据世界贸易组织技术性贸易壁垒（TBT）委员会发布的《关于制定国际标准、指南和建议的原则的决定》中确立的国际公认标准化原则制定的。 =====意义和用途====== 4.1 根据氧化镁含量的标称值和最小值，该分类将定义的耐火砖类型（铬砖除外）划分为不同的类别。铬砖被视为单独的类别，不考虑氧化镁含量。此类类别通常用于将定义的类型与特定工业应用相关联，以及开发产品或采购规范。

1.1 This classification categorizes machine-made refractory brick defined as chrome, chrome-magnesia, magnesia-chrome, and magnesia brick (see 3.1 ). It does not cover products made from electrically fused magnesium oxide or products made by fusion casting. Its purpose is to describe classes distinguished by obvious differences in magnesium oxide (MgO) content except for chrome brick. 1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. 1.3 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee. ====== Significance And Use ====== 4.1 This classification categorizes the defined types of refractory brick, with the exception of chrome brick, into distinct classes based on a nominal and minimal value for magnesium oxide content. Chrome brick are treated as a separate class without reference to magnesium oxide content. Such classes have historically been generally useful in relating the defined types to specific industrial applications and in developing product or purchasing specifications.