High Strength Steel Design Based On Empirical Electron Theory Of Solids And Molecules

At presents, the design of the damage and protective material are lack of scientific methods and effective guidance to the research basically using "trial and error method". "Trial and error method" not only spends a lot of money, but also difficult to make the material performance has large span. On the other hand, since empirical electron theory of solid and molecules(EET for short) was founded, the scholars have studied the valence electron structure(VES for short) of a variety of materials and the quantitative relationship with the static property, but did not involve dynamic performance. In view of the above two problems, this paper presents using EET guide dynamic high strength steel design. By derivating relationship between volume and strain rate under dynamic or static load, author improved the static strength theory model. The researchers developed new VES parameters and put forward the theory of adiabatic shear electronic strength and spall strength model of electronic theory. 42 Cr Ni2Mo WV was designed due to model, and deeply researched for verification. The major conclusions are as follow.Stress ball tensor stress state analysis was used in valence electron structure calculation of EET for the first time. Volume stress(stress tensor) is about a third of the total stress when quasi static loading(strain rate is about 10-3 s-1); Volume stress ratio is more than 1/3 under dynamic loading(strain rate is about 10-3 s-1 ~ 10-4 s-1). Thus, with the improvement of compressive strain rate, the crystal lattice of the material parameters will reduce gradually. So in dynamic loading, the valence electron structure of the material change.New valence electron structure parameters were built due to dislocation. Ef, the single dislocation valence electron structure parameter, quantitatively describes the weakening effect. If, dislocation delivery valence electron structure parameter, Pf, dislocation pinning valence electron structure parameter and Sf, valence electron structure parameter containing replacement atom, quantitatively reflect strengthen effect when delivery, pinning and replacement.Static strength valence electron structure model are improved. Improved the strengthening coefficient S and strengthening the weight W, puts forward a new model of the static strength:?b= ?bα-Fe(1 + Sα-Fe-CWα-Fe-C+ ∑Sα-Fe-C-MWα-Fe-C-M+ ∑Sε-(Fe,M)3CWε-(Fe,M)3C). By contrast, the error with actual strength is about 5%.Adiabatic shear strength model and spallation strength model were put forward. On the basis of the static model, by multiply dynamic reinforcement index P(corresponding to the adiabatic shear strength), Q(corresponding to the spallation strength model) to each phase, author propose adiabatic shear strength model ?SP= ?bα-FePα-Fe(1 + Sα-Fe-CWα-Fe-CPα-Fe-C+ Sε-(Fe,M)3CWε-(Fe,M)3C Pε-(Fe,M)3C) for the first time and spallation strength model ?SP= ?bα-FeQα-Fe(1 +Sα-Fe-CWα-Fe-CQα-Fe-C+ Sα-Fe-C-MWα-Fe-C-MQα-Fe-C-M+Sε-(Fe,M)3CWε-(Fe,M)3CQε-(Fe,M)3C). P and Q are associated with valence electron structure and volume change under dynamic loading. And each phase has different strength increment.Change of the stress ball tensor in stress tensor analysis is put forward in the criterion for adiabatic shear band formation. With strain rate increase, when the volume stress accounts for half of total stress, adiabatic shearing occurs. Adiabatic shear process namely volume expansion process, first the volumetric stress release, after deformation stress is released.The release of volumetric stress "stress collapse". After "stress collapse", deformation stress maintains at a low level.According to the strength model, 42 Cr Ni2Mo WV alloy steel was designed and manufactured. Static strength, adiabatic shearing strength and spallation strengths were calculated and detected. The highest quasi static strength of low temperature tempering is about 2100 MPa, and forecast 1900 MPa, relative error 10%. The strength of the medium temperature tempering is about 1500 MPa, and forecast 1559 MPa, relative error 4%; Under the strain rate 2000 s-1, the predict dynamic strength is 2736 MPa, experimental value roughly 2700-2800 MPa; Compared with experiment spallation strength, error of theory spallation strength of is 0.0% to 7.6%.