热处理
熱處理
열처리
HEAT TREATMENT
2014年
4期
1-7
,共7页
传质系数%碳扩散系数%解析解%数值解%集中参数法
傳質繫數%碳擴散繫數%解析解%數值解%集中參數法
전질계수%탄확산계수%해석해%수치해%집중삼수법
mass transfer coefficient%carbon diffusion coefficient%analytical solution%numerical solution%lumped parameter method
用数值计算法模拟了钢箔的渗碳过程。根据模拟试验结果，按照钢箔渗碳试验的常用公式计算出工件表面传质系数β。结果表明，钢箔厚度、渗碳时间和钢箔的碳扩散系数对按常用公式计算的β系数值有明显的影响，该计算值总是小于模拟试验前的β系数设定值（即真值），而且随着钢箔中碳扩散系数的减小而减小。常用公式仅适用于钢箔的碳扩散系数为无限大的条件，否则所计算的β系数值是不正确的，并显示出受其他试验因素影响的虚假信息。常用公式的不当引用是造成长期来β系数的计算值不准确、可比性差的主要原因。根据钢箔渗碳方程的解析解，提出了新的计算β系数的方法，采用新方法可以求得接近真值的β系数，而且还能求得试验材料的碳扩散系数。
用數值計算法模擬瞭鋼箔的滲碳過程。根據模擬試驗結果，按照鋼箔滲碳試驗的常用公式計算齣工件錶麵傳質繫數β。結果錶明，鋼箔厚度、滲碳時間和鋼箔的碳擴散繫數對按常用公式計算的β繫數值有明顯的影響，該計算值總是小于模擬試驗前的β繫數設定值（即真值），而且隨著鋼箔中碳擴散繫數的減小而減小。常用公式僅適用于鋼箔的碳擴散繫數為無限大的條件，否則所計算的β繫數值是不正確的，併顯示齣受其他試驗因素影響的虛假信息。常用公式的不噹引用是造成長期來β繫數的計算值不準確、可比性差的主要原因。根據鋼箔滲碳方程的解析解，提齣瞭新的計算β繫數的方法，採用新方法可以求得接近真值的β繫數，而且還能求得試驗材料的碳擴散繫數。
용수치계산법모의료강박적삼탄과정。근거모의시험결과，안조강박삼탄시험적상용공식계산출공건표면전질계수β。결과표명，강박후도、삼탄시간화강박적탄확산계수대안상용공식계산적β계수치유명현적영향，해계산치총시소우모의시험전적β계수설정치（즉진치），이차수착강박중탄확산계수적감소이감소。상용공식부괄용우강박적탄확산계수위무한대적조건，부칙소계산적β계수치시불정학적，병현시출수기타시험인소영향적허가신식。상용공식적불당인용시조성장기래β계수적계산치불준학、가비성차적주요원인。근거강박삼탄방정적해석해，제출료신적계산β계수적방법，채용신방법가이구득접근진치적β계수，이차환능구득시험재료적탄확산계수。
Carburizing process of steel foil was simulated by using numerical method.According to the simulation test result,mass transfer coefficient at workpiece surface,β,was calculated with a commonly used formula for steel foil carbonizing test.The results indicate that foil thickness,carburizing time and carbon diffusion coefficient in the foil will exert an appreciable influence on the value ofβcoefficient calculated by the commonly used formula,and that the calculated βvalue is always less than the set βvalue (i.e.,truth value)before the simulation test and reduces with the decrease in carbon diffusion coefficient in the foil.The commonly used formula is suitable only when carbon diffusion coefficient in the foil is unlimited,otherwise the calculated βvalue is not correct,and will give out false information that other test factors exert an influence on the calculated βvalue.Over a long period of time,the calculated βcoefficient values are inaccurate and difficult to be compared each other,which arise mainly from unsuitable quote of the commonly used formula.Based on analytical solution of carburizing equation of the steel foil,a new method of calculating the βcoefficient,by which the βcoefficient near truth value and the carbon diffusion coefficient in the tested material may be obtained,has been given.
