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首页> 外文会议>63rd World Foundry Congress Sep 12-18, 1998 Budapest, Hungary >AMELIORATION DE LA RESISTANCE A LA CORROSION DES LAITONS ET DES CUPRO-ALUMINIUMS MOULES PAR TRAITEMENT THERMIQUE
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AMELIORATION DE LA RESISTANCE A LA CORROSION DES LAITONS ET DES CUPRO-ALUMINIUMS MOULES PAR TRAITEMENT THERMIQUE

机译：通过热处理提高黄铜和模制铝的耐腐蚀性

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Good use is made of the excellent performance of copper alloys in many corrosive environments. They are subject, however, to a special form of deterioration ― selective corrosion. This process may take the form of a slow generalized attack of the surface or of pitting, sometimes dangerous. Suitable heat treatments, deduced from the equilibrium diagrams, yield substantial improvement. In the case of aluminium bronzes, generalized corrosion can be avoided by observing the simple rule relating admissible aluminium content to nickel content. We show that the tendency to pitting as evaluated by a particular potentio-kinetic test is sensitive both to chemical composition and to the differences in structure observed between the as-cast and more or less deeply annealed structures. A customer may be led to state more precise composition limits for aluminium and nickel within the existing standards and to require corrosion-proofing annealing. Brasses are used primarily in water that is fresh but may be more or less aggressive depending on the country or area. Two-phase foundry alloys may in this case be corroded by dezincifi-cation. An annealing treatment may be devised that isolates the beta prime phase in the middle of the alpha phase, the proportion of which is increased. This change of structure retards the kinetics of corrosion. Longer lives can be attained by using brasses having a lower equivalence factor and thus greater mechanical strength.
机译：在许多腐蚀性环境中，铜合金的出色性能得到了很好的利用。但是，它们会遭受一种特殊形式的劣化-选择性腐蚀。该过程可能采取缓慢的表面普遍腐蚀或点蚀的形式，有时很危险。由平衡图推导出的合适的热处理产生了显着的改善。对于铝青铜，可以通过遵守将允许的铝含量与镍含量相关的简单规则来避免普遍腐蚀。我们表明，通过特定的电位动力学测试评估的点蚀趋势对化学成分以及铸态和或多或少的深度退火结构之间观察到的结构差异均敏感。可能会导致客户要求在现有标准中规定更精确的铝和镍成分限制，并要求进行防腐蚀退火。黄铜主要用于新鲜的水中，但根据国家或地区的不同，腐蚀性可能会有所不同。在这种情况下，两相铸造合金可能会被脱锌腐蚀。可以设计出一种退火处理方法，该方法可以在α相的中间隔离β主相，并增加其比例。这种结构上的改变阻碍了腐蚀的动力学。通过使用当量系数较低，因此机械强度较高的黄铜，可以延长使用寿命。

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