13MnNiMoR鋼熱沖壓封頭沖擊韌度顯著降低原因分析13MnNiMoR鋼熱沖壓封頭沖擊韌度顯著降低原因分析Cause Analysis on Significant Decrease of Impact Toughness of Hot-pressed 13MnNiMoR Steel Vessel Heads 13MnNiMoR鋼板熱沖壓成型封頭的沖擊性能存在不合格現象。采用化學成分分析、力學性能測試、金相檢驗及模擬熱處理等方法，對13MnNiMoR鋼封頭沖擊韌度顯著降低的原因進行了分析。結果表明：對于較厚的封頭，正火處理后的冷卻速率嚴重不足，致使碳化物沿鐵素體晶界析出，且在高溫回火過程中碳化物再次長大；在沖擊過程中，封頭在外力作用下容易在碳化物析出位置發生斷裂，導致封頭的沖擊韌度顯著降低至不合格。 The impact toughness of hot-pressed 13MnNiMoR steel vessel heads was unqualified. By means of chemical composition analysis, mechanical property testing, metallographic examination, simulated heat treatment and so on, the significant decrease reasons of impact toughness of the hot-pressed 13MnNiMoR steel vessel heads were analyzed. The results show that:the cooling speed of thick vessel heads after normalization treatment was seriously insufficient, which led to the carbide precipitation along the ferrite grain boundaries, and then carbide grew up in the process of high-temperature tempering process; in the impact process, the vessel heads were easy to fracture at the position of carbide precipitation under the exogenic action, leading to the significant decrease and disqualification of impact toughness of the vessel heads.
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