The methods of spectral, x-ray phase and microprobe analysis show that genuine Damascus steel is a high-purity unalloyed high-carbon steel with a high phosphorus content. It is shown that phosphorus in an amount of fr...The methods of spectral, x-ray phase and microprobe analysis show that genuine Damascus steel is a high-purity unalloyed high-carbon steel with a high phosphorus content. It is shown that phosphorus in an amount of from 0.1% to 0.2%, having a high liquation coefficient, contributes to the process of segregation of carbon in interdendritic zone in the process of crystallization. Interdendritic zone formed carbon clusters, in the process of forging transform into oblong carbides cementite. The main physical and chemical factors affecting the formation of oblong carbides are revealed. The hardness of carbide layers was determined, which was about 920 HV. The hardness of the troostite matrix was amounted about 475 HV. It is established that the cutting edge of the blade knife of Damascus steel is nothing more than a “micro-saw” consisting of parallel carbide and troostite layers. Tests are conducted on the preservation of the cutting edge sharpness of the blades knife of homogeneous structure of steel У15А (Russian) and the layered structure of genuine Damascus steel Ds15P (Indo-Persian). Found that with little effort cut (to 4 kg) ancient Damascus steel (Ds15P) shows a greater number of cuts than the modern instrument steel У15А. With an increase, force on the cutting edge from 6 kg to 12 kg carbon Tool steel is showed a more number of cutting on the 25% than in genuine Damascus steel. The fatigue crack propagation in the true Layered structure of Damascus steel Ds15P occurs for a greater number of cycles than in a homogeneous structure of the steel У15А. The blade knife of genuine Damascus steel, in terms of fatigue reliability (survivability), has almost 2 times longer service life than the blade knife of the modern carbon tool steel type У15А. It is proved that loss in cutting ability of a genuine Damascus steel compensates increased the reliability (“survivability”) of the blade knife with fatigue loads.展开更多
It has been revealed that the structure of the transverse and longitudinal parts of the genuine Damascus knife of the XVIII century consists of troostite-carbide of the banding. The microhardness of the troostite laye...It has been revealed that the structure of the transverse and longitudinal parts of the genuine Damascus knife of the XVIII century consists of troostite-carbide of the banding. The microhardness of the troostite layers is 450 HV;the carbide layers reach 950 HV. It is shown that such a banding structure in hardness will have a huge impact on the formation of a naturally patterned genuine Damascus structure. It is established that the form of the main drawings of the genuine Damascus pattern consists of separate elements of the topographic contour: hollows, hills, saddles, crosses and wavy dunes. It is shown that the damask pattern is a set of individual elements of the macrostructure alternating in a disordered form on different local areas of the surface. It is established that the destruction of genuine Damascus steels occurs under the action of two or more mechanisms, during the implementation of which traces remain on the surface of the fractures in the form of relief details of a mixed type. The mechanisms of mixed destruction are a combination of intragrain cleavage, micropore fusion and intergrain cracking. It is established that in order to implement the mechanism of separation of the main crack in the direction of the chopping blow, an optimum is required in the dispersion of troostite (61.8%) and carbide (38.2%) layers in genuine Damascus steel, the ratio of their volumes obeys the golden section rule. It is established that the damask pattern, consisting of elements of sinuous lines of a topographic contour, does not significantly affect the level of mechanical properties. This factor is a category of the quality of banding structures in genuine Damascus steel.展开更多
文摘The methods of spectral, x-ray phase and microprobe analysis show that genuine Damascus steel is a high-purity unalloyed high-carbon steel with a high phosphorus content. It is shown that phosphorus in an amount of from 0.1% to 0.2%, having a high liquation coefficient, contributes to the process of segregation of carbon in interdendritic zone in the process of crystallization. Interdendritic zone formed carbon clusters, in the process of forging transform into oblong carbides cementite. The main physical and chemical factors affecting the formation of oblong carbides are revealed. The hardness of carbide layers was determined, which was about 920 HV. The hardness of the troostite matrix was amounted about 475 HV. It is established that the cutting edge of the blade knife of Damascus steel is nothing more than a “micro-saw” consisting of parallel carbide and troostite layers. Tests are conducted on the preservation of the cutting edge sharpness of the blades knife of homogeneous structure of steel У15А (Russian) and the layered structure of genuine Damascus steel Ds15P (Indo-Persian). Found that with little effort cut (to 4 kg) ancient Damascus steel (Ds15P) shows a greater number of cuts than the modern instrument steel У15А. With an increase, force on the cutting edge from 6 kg to 12 kg carbon Tool steel is showed a more number of cutting on the 25% than in genuine Damascus steel. The fatigue crack propagation in the true Layered structure of Damascus steel Ds15P occurs for a greater number of cycles than in a homogeneous structure of the steel У15А. The blade knife of genuine Damascus steel, in terms of fatigue reliability (survivability), has almost 2 times longer service life than the blade knife of the modern carbon tool steel type У15А. It is proved that loss in cutting ability of a genuine Damascus steel compensates increased the reliability (“survivability”) of the blade knife with fatigue loads.
文摘It has been revealed that the structure of the transverse and longitudinal parts of the genuine Damascus knife of the XVIII century consists of troostite-carbide of the banding. The microhardness of the troostite layers is 450 HV;the carbide layers reach 950 HV. It is shown that such a banding structure in hardness will have a huge impact on the formation of a naturally patterned genuine Damascus structure. It is established that the form of the main drawings of the genuine Damascus pattern consists of separate elements of the topographic contour: hollows, hills, saddles, crosses and wavy dunes. It is shown that the damask pattern is a set of individual elements of the macrostructure alternating in a disordered form on different local areas of the surface. It is established that the destruction of genuine Damascus steels occurs under the action of two or more mechanisms, during the implementation of which traces remain on the surface of the fractures in the form of relief details of a mixed type. The mechanisms of mixed destruction are a combination of intragrain cleavage, micropore fusion and intergrain cracking. It is established that in order to implement the mechanism of separation of the main crack in the direction of the chopping blow, an optimum is required in the dispersion of troostite (61.8%) and carbide (38.2%) layers in genuine Damascus steel, the ratio of their volumes obeys the golden section rule. It is established that the damask pattern, consisting of elements of sinuous lines of a topographic contour, does not significantly affect the level of mechanical properties. This factor is a category of the quality of banding structures in genuine Damascus steel.
