中厚钢板中的硫化物夹杂及其对冷弯性能的影响

安钢中厚钢板中普遍分布有长条状硫化物夹杂。硫化物夹杂对中厚钢板冷弯性能的影响取决于其数量、尺寸和分布形态。尺寸较小且分散分布的硫化物夹杂对冷弯性能影响不大，而尺寸较大且集中分布的硫化物夹杂可作为裂纹源，直接引起中厚钢板冷弯开裂，对冷弯性能影响很大。在冷弯变形过程中，应力集中首先使硫化物夹杂裂开，或使夹杂与金属基体分离产生显微孔洞，这些孔洞随变形过程不断长大、联接形成显微裂纹和内裂，然后进一步扩展导致中厚钢板的冷弯开裂。因此，要提高中厚钢板的冷弯性能，必须采取一定的技术措施，降低钢中硫含量，减少硫化物夹杂的数量．改善硫化物夹杂的尺寸和分布形态，降低钢板冷弯对硫化物形态的敏感性。

Sulfide Inclusion in Medium and Heavy Plate and Its Effect on Cold Bending Properties

Striplike sulfide inclusions are generally distributed in medium and heavy plate produced by Anyang Iron and Steel Corp.The influence of sulfide inclusion on cold bending properties of medium and heavy plate depends on quantity,size and distributed morphology of the inclusions.The sulfide inclusions which are small in size and dispersively distributed have slight influence on cold bending properties,however,those sulfide inclusion which are bigger in size and distributed in clusters may act as crack sources,will directly lead to cracking of medium and heavy plate at cold bending,have a very great influence on cold bending properties.During cold bending deformation,stress concentration first causes sulfide inclusion to crack or makes inclusions separate from metal matrix and generate micro holes which increase in size continuously with deforming process,form microcracks and internal cracks when connected together,and then the cracks further expand causing medium and heavy plate to crack at cold bending.Therefore,in order to enhance cold bending properties of medium and heavy plate,a certain technical measures have to be taken so as to reduce sulfur content in steel,decrease the quantity of sulfide inclusions,improve their sizes and distributed morphology,reduce the sensitivity of steel plate cold bending to sulfide morphology.