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耐磨板探伤不合原因分析及改进措施

所属分类:行业资讯 发布时间:2020-10-19 11:27:36 来源:http://www.lcnmb500.com 浏览量:

HARDOX500耐磨板探伤不合原因分析及改进措施

Reason analysis and improvement measures of hardox500 wear plate

一、关注重点合金元素和钢坯加热工艺

1、 Focus on key alloy elements and billet heating process

从炼钢工序开始, 在出钢过程中时保证一次加入足量铌铁合金,采取炼钢工序强化精炼设备的维护,同时在保证铸机连续生产的前提下延长钢水的软吹时间,促进钢中夹杂物的上浮,避免LF炉处理后期补加;由于部分Nb等合金元素没有充分固溶到基体中,没有发挥出合金元素的作用,还造成hardox500耐磨板微裂纹,应控制钢坯加热温度和时间,使钢坯烧透,这样既可促进偏析元素的扩散溶解,又不至于使hardox500耐磨板组织中的奥氏体晶粒异常长大。保证钢坯加热时炉膛温度在1170℃,加热时间4h以上,使析出物充分固溶。

From the steelmaking process, In the tapping process, sufficient niobium iron alloy should be added at one time, and the steel-making process was adopted to strengthen the maintenance of refining equipment. At the same time, under the premise of continuous production of the caster, the soft blowing time of molten steel was extended to promote the floating of inclusions in the steel, so as to avoid the supplement in the later stage of LF furnace treatment. Because some alloy elements such as NB were not fully dissolved into the matrix, they did not play the role of alloy elements, It is suggested that the heating temperature and time of billet should be controlled to make the billet burn through, which can promote the diffusion and dissolution of segregation elements and prevent the abnormal growth of austenite grains in HARDOX 500 wear-resistant plate. Ensure that the furnace temperature is 1170 ℃ and the heating time is more than 4 h when the billet is heated, so that the precipitates are fully solid solution.

一、关注重点合金元素和钢坯加热工艺

1、 Focus on key alloy elements and billet heating process

从炼钢工序开始, 在出钢过程中时保证一次加入足量铌铁合金,采取炼钢工序强化精炼设备的维护,同时在保证铸机连续生产的前提下延长钢水的软吹时间,促进钢中夹杂物的上浮,避免LF炉处理后期补加;由于部分Nb等合金元素没有充分固溶到基体中,没有发挥出合金元素的作用,还造成hardox500耐磨板微裂纹,应控制钢坯加热温度和时间,使钢坯烧透,这样既可促进偏析元素的扩散溶解,又不至于使hardox500耐磨板组织中的奥氏体晶粒异常长大。保证钢坯加热时炉膛温度在1170℃,加热时间4h以上,使析出物充分固溶。


hardox500耐磨板探伤不合原因分析及改进措施(图1)

From the steelmaking process, In the tapping process, sufficient niobium iron alloy should be added at one time, and the steel-making process was adopted to strengthen the maintenance of refining equipment. At the same time, under the premise of continuous production of the caster, the soft blowing time of molten steel was extended to promote the floating of inclusions in the steel, so as to avoid the supplement in the later stage of LF furnace treatment. Because some alloy elements such as NB were not fully dissolved into the matrix, they did not play the role of alloy elements, It is suggested that the heating temperature and time of billet should be controlled to make the billet burn through, which can promote the diffusion and dissolution of segregation elements and prevent the abnormal growth of austenite grains in HARDOX 500 wear-resistant plate. Ensure that the furnace temperature is 1170 ℃ and the heating time is more than 4 h when the billet is heated, so that the precipitates are fully solid solution.

二、提高钢水纯净度,减少非金属夹杂物含量

2、 Improve the purity of molten steel and reduce the content of non-metallic inclusions

从扫描 电镜、能谱仪分析结果看出,hardox500耐磨板裂纹处主要以大型硫化物等非金属夹杂物为主。所以在生产有探伤要求的hardox500耐磨板时,为保证钢水质量,对铁水进行深脱硫,并加优质废钢,以减少外来夹杂物对钢水纯净度的影响;另一方面强化现场操作,提高终点控制水平,减少点吹次数,降低钢水中的氧含量,从而降低钢中夹杂物总量,保证LF炉埋弧良好,防止碳棒电离空气污染钢水。在保证生产节奏的前提下,对钢水进行真空脱气处理。提高钢水纯净度,减少夹杂物的含量。

The results of SEM and EDS show that the cracks of HARDOX 500 wear-resistant plate are mainly composed of large-scale sulfide and other non-metallic inclusions. Therefore, in order to ensure the quality of molten steel, deep desulfurization and high-quality scrap are added to ensure the quality of hardox500 wear-resistant plate, so as to reduce the influence of foreign inclusions on the purity of molten steel; on the other hand, strengthen the field operation, improve the end-point control level, reduce the number of spot blowing, reduce the oxygen content in molten steel, so as to reduce the total amount of inclusions in steel and ensure the submerged arc of LF furnace Good, to prevent carbon rod ionizing air pollution of molten steel. On the premise of ensuring the production rhythm, the molten steel is degassed in vacuum. Improve the purity of molten steel and reduce the content of inclusions.

三、改善连铸坯质量及轧钢工艺

3、 Improvement of continuous casting slab quality and rolling process

钢水及连铸坯质量是产生探伤不合的内在根本原因。尤其是连铸坯内部质量可直接影响探伤结果,强化连铸坯内部质量是提高探伤板合格率的有效手段。应降低连铸坯过热度,采用连铸末端动态轻压下技术减轻连铸坯的中心偏析,强化连铸坯下线堆垛缓冷工艺,保证铸坯堆冷48h,促使钢中[H]的向外扩散。在轧钢工序加大粗轧阶段单道次压下量,增加压缩比,使变形充分渗透,起到焊合铸坯中的疏松和显微气孔的作用,并合理控制轧制温度,保证冷却水配比合理,实现均匀冷却,以减少hardox500耐磨板内部应力,防止hardox500耐磨板产生微裂纹,轧制后hardox500耐磨板下线缓冷24小时。

The quality of molten steel and continuous casting billet is the internal root cause of unqualified flaw detection. In particular, the internal quality of continuous casting slab can directly affect the results of flaw detection, and strengthening the internal quality of continuous casting slab is an effective means to improve the pass rate of flaw detection plate. The superheat of continuous casting slab should be reduced, dynamic soft reduction technology at the end of continuous casting should be adopted to reduce the central segregation of continuous casting slab, and the slow cooling process of continuous casting slab stacking off-line should be strengthened to ensure the billet stacking cooling for 48 h and promote the outward diffusion of [H] in steel. In order to reduce the internal stress of hardox500 wear-resistant plate and prevent microcracks in hardox500 wear-resistant plate, it is necessary to increase the single pass reduction and compression ratio in the rough rolling stage, so as to fully penetrate the deformation, play the role of porosity and micro pores in the welded slab, and reasonably control the rolling temperature to ensure the reasonable proportion of cooling water and realize uniform cooling, so as to reduce the internal stress of hardox500 wear-resistant plate and prevent micro crack of hardox500 wear-resistant plate Slow cooling for 24 hours.

通过以上措施,钢水中A、B、C、D类夹杂物均在1.0级以下,纯净度得到明显提高;hardox500耐磨板铸坯中心偏析得到明显改善;铸坯中微小缺陷被充分焊合,探伤合格率提高30%。

Through the above measures, the A, B, C, D inclusions in the molten steel are all below 1.0, the purity is obviously improved; the center segregation of hardox500 wear-resistant plate is significantly improved; the small defects in the billet are fully welded, and the qualified rate of flaw detection is increased by 30%.