文章信息/Info

Title:

 Computer Analysis and Elimination to Metallurgical Defects ��
in Tool�睤ie Steel Deposit Prepared by Spray Forming

作者:

張勇; 張國(guó)慶; 李周; 袁華; 許文勇

(中航工業(yè)北京航空材料研究院 先進(jìn)高溫結(jié)構(gòu)材料國(guó)防科技重點(diǎn)實(shí)驗(yàn)室，北京100095)

Author(s):

 ZHANG Yong; ZHANG Guoqing; LI Zhou; YUAN Hua; XU Wenyong

關(guān)鍵詞:

噴射成形; 工模具鋼; 沉積坯; 計(jì)算模擬

DOI:

10.7502/j.issn.1674-3962.2012.12.08

文獻(xiàn)標(biāo)志碼:

A

摘要:

用有限元方法計(jì)算分析了噴射成形工模具鋼沉積坯內(nèi)部疏松等冶金缺陷的成因，并計(jì)算、驗(yàn)證了熱等靜壓或鍛軋等熱加工消除內(nèi)部缺陷的過(guò)程。研究表明，噴射成形工模具鋼沉積坯粥狀層補(bǔ)縮不足和冷卻收縮產(chǎn)生的熱應(yīng)力是造成坯體中疏松等冶金缺陷的重要原因。熱等靜壓采用的溫度為1 170 ℃，鍛造加工溫度也能達(dá)到1 150 ℃，在這樣溫度下，工模具鋼表現(xiàn)出一定的塑性，高溫高壓的熱加工過(guò)程，對(duì)材料內(nèi)部的冶金缺陷起到了一定的彌和作用。試驗(yàn)結(jié)果表明，經(jīng)歷熱加工過(guò)程后的工模具鋼內(nèi)部的冶金缺陷明顯減少。熱等靜壓或鍛軋等熱加工可有效減少噴射成形工模具鋼坯體內(nèi)部的疏松等缺陷，熱鍛、熱軋是消除沉積坯內(nèi)部冶金缺陷的重要方法。另外，與Ar氣相比，采用N��2做霧化氣體的噴射成形工模具鋼沉積坯，由于高溫下氣體和合金元素的反應(yīng)，沉積坯內(nèi)部的含氣式疏松很少。因此，采用N��2噴射成形制備的工模具鋼經(jīng)熱加工后，沉積坯密度更接近理論密度。��

Abstract:

 With the help of finite element method computing, the formation of metallurgical defects, such as hot tear, porosity etc was analyzed and the process of reducing the defects was verified in the paper. We found that the hot tear and porosity in tool�瞕ie steel are caused by the pull stress engendered by cooling contract and insufficient feeding of liquid metal in local position in billet. The hot isostatic pressing temperature employed is 170 ℃，and forging processing temperature can reach 150 ℃, die steel exhibits a certain plasticity at these temperatures, the hot processing can close metallurgical defects inside of the material after the thermal processing of the high temperature and pressure. Forging and hot roll process are important method to decrease and eliminate the looseness and porosity in deposit of tool�瞕ie steel. Further, as compared with the Ar gas, for tool and die steel prepared by spray forming thermal processing with the N��2, deposition green density can close to the theoretical density.��