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球墨铸铁管、铸铁管、铸钢管的区别

作者: -1    发布时间: 2018-07-20    次浏览
与铸铁管相比,球墨铸铁管在强度方面具有的优势。球墨铸铁管的抗拉强度是60k,而铸铁管的抗拉强度只有31k。球墨铸铁管的屈服强度是40k,而铸铁管并没有显示出屈服强度,并且较终出现断裂。球墨铸铁管的强度、成本比远远优于铸铁管。

Ductile iron pipe has advantages in strength over cast iron pipe. Ductile iron pipe tensile strength is 60k, while cast iron pipe tensile strength is only 31k. Ductile iron pipe's yield strength is 40k, while the ductile iron pipe does not show the yield strength, and the ductile iron pipe eventually breaks. The strength and cost ratio of ductile iron pipe is much better than that of cast iron pipe.


球墨铸铁管


球墨铸铁管的强度和铸钢的强度是可比的。球墨铸铁管具有更高的屈服强度,其屈服强度较低为40k,而铸钢管的屈服强度只有36k。在大部分市政应用领域,如:水、盐水、蒸汽等,球墨铸铁管的耐腐蚀性和抗氧化性都超过铸钢管。由于球墨铸铁管的球状石墨微观结构,在减弱振动能力方面,球墨铸铁管优于铸钢管,因此更加有利于降低应力。选择球墨铸铁管的一个重要的原因在于球墨铸铁管比铸钢管成本低。球墨铸铁管的低成本使得这种材料更加受欢迎,铸造效率更高,也较少了球墨铸铁管的机加工成本。作为钢的替代品,1949年人类开发了球墨铸铁管。铸钢含碳量少于0.3%,而铸铁管和球墨铸铁管含炭量量则至少为3%。铸钢管中的低含碳量使得作为游离石墨存在的碳不会形成结构薄片。铸铁内的碳天然形式是游离石墨薄片形式。在球墨铸铁内,这种石墨薄片通过特殊的处理方法变化成微小的球体。这种改进后的球体使得球墨铸铁比铸铁和钢相比具有更加优异的物理性能。正是这种碳的球状微观结构,使得球墨铸铁管具有更加良好的展延性和抗冲击性,而铸铁内部的薄片形式导致铸铁没有展延性。通过铁素体基体可获得较佳的展延性。

The strength of ductile iron pipe is comparable to that of cast steel. Ductile iron pipe has a higher yield strength, with a lower yield strength of 40k, while cast steel pipe has a yield strength of only 36k. In most municipal applications, such as water, salt water, steam, etc., ductile iron pipes are more corrosion resistant and oxidation resistant than cast steel pipes. Because of the spheroidal graphite microstructure of ductile iron pipe, ductile iron pipe is superior to cast steel pipe in reducing vibration capability, so it is more beneficial to reduce stress. An important reason to choose ductile iron pipe is that ductile iron pipe costs less than cast steel pipe. The low cost of ductile iron pipe makes the material more popular, the casting efficiency is higher, and the machining cost of ductile iron pipe is less. As an alternative to steel, ductile iron pipes were developed in 1949. Cast steel contains less than 0.3% carbon, while cast iron pipes and ductile iron pipes contain at least 3% carbon. The low carbon content in cast steel tubes prevents the carbon present as free graphite from forming structural sheets. The natural form of carbon in cast iron is free graphite sheet form. In ductile iron, the graphite sheet is changed into tiny spheres by special treatment. The improved sphere gives ductile iron better physical properties than cast iron or steel. It is the spheroidal microstructure of carbon that makes ductile iron pipe have better ductility and impact resistance, while the inner flake form of cast iron causes no ductility of cast iron. Better ductility can be obtained by ferrite matrix.

因此,球墨铸铁管的压力负载部件都经过铁素体化退火周期的工艺处理后,球墨铸铁管内部的球状结构也能够消除铸铁内部的薄片石墨容易产生的裂缝现象。在球墨铸铁的微观照片中,可以看见裂缝游行到石墨球后终止。在球墨铸铁管行业内,这些石墨球称为“裂缝终结者”,因为它们具有阻止断裂的能力。

Therefore, the nodular structure in ductile iron pipe can also eliminate the cracks easily caused by flake graphite in cast iron after the pressure load parts of ductile iron pipe have been processed by ferrite annealing cycle. In microscopic photos of ductile iron, cracks can be seen marching to the graphite ball and ending. In ductile iron pipe industry, these graphite balls are called "crack terminator" because of their ability to prevent fracture.