Research And Development Of New Stainless Steel For Chopping Knives And Scissors

Slicing knives and Scissors are the main products of hardware,which is essential to people,s life.Presently,most of the corporations ,which manufacture kinves and scissors in our country are private enterprises,centralize in GuangDong Province and ZheJiang Province.On the whole,the quality of hardware products manufactured in our country cannot compare with the products made in the developed countries.Our products are still staying on the level of low-grade and low-price.Only can our products hold the market through low-price when suffering from branded products which are produced by some famous enterprises in the developed countries.There are four main problems which trouble the companies manufacturing slicing knives and scissors:First, the research and development of new materials,it's applications and manufacturing techniques are still insufficient, lacking highly-skilled workers. Second,the investgations into the technology for heating processing need improve,companies need introduce advanced equipment. Third,grinding technology,polishing technology and surface treatment need to be improved.In order to develop new materials and set out their heating processing,the paper bases on the conditions of the manufacturing companies in DaZu county,ChongQing,and the curerrent situation of the metal materials for and the prospect of the slicing knives and scissors,according to the theory of metallography and some principles about stainless steels,one component called CD-1 steel was designed.The chief alloy elements were Carbon(0.41%),Chromium(9.74%) and Silicon(2.43%),with a little content of Manganese.Then,some research works about the material's key performances and its heating processing were investigated.The design of CD-1 steel broke through the traditional concept about the stainless steel and reduced the content of Chromium which is only about 10 percent,by adding a remarkable highly percent of Silicon and strictly controlling the content of carbon,phosphorus and sulfur in the steel-which made the steel perform very well in all aspects of properties.The new design theory will bring a new thread about developing materials for slicing knives and scissors.Sheets with a thickness of 3mm were obtained by three hot rolling passes and annealing,the research results indicated that the matrix was highly unanimous with fine close grains, mechanical properties of the steel sheets in all its directions(TD,RD and 45°)were rather unanimous,showed a high strength and good plastic property.The investigations into the heating processing showed that the appropriate quenching temperature for CD-1 steel,which was used for manufacturing slicing knives and scissors was between 1045℃and 1060℃.The structures of CD-1 steel when quenched under this temperature range were quenched martensite and a handful of residual austensite,with a degree of hardness above HRC 60.Structures became coarse and rough when the quenching temperature is above 1060℃.Inorder to maintain a high degree of hardness which is essential to slicing knives and scissors,the tempering range would better be under 200℃,with the temper time about 1.5 hours.So the final heat-treatment was laied down ,quenching from 1045℃to 1060℃,then,1.5 hours tempering 190℃.Then,bending test samples,quenching at 1060℃then tempering at 190℃with 1.5 hours, were prepared.The results showed a high flexural strength surpassed 3600MPa,a break deflection f bb beyond 11mm. The topogram of bend fracture showed a mixed fractured,with a characteristic of plastic fracture and cleavage fracture.Galvano-chemistry etching test of the CD-1 steel,5Cr15MoV steel and 4Cr13 steel indicated that 5Cr15MoV steel had the best corrosion-resistant,then 4Cr13 steel and CD-1 steel when they had the same final heat-treatment and surface roughness.Among the 0Cr13 steel,CD-1 steel and 5Cr15MoV steel,resistance to high temperature oxidation test from 900℃to 1150℃showed that the high-temperature oxidation resistance of CD-1 steel was the best among the steels involved.The unit area weight-loss ratio of CD-1 steel was rather lower than 5Cr15MoV steel and 4Cr13 steel.The slicing knives made of CD-1 steel displayed excellent properties which brought in much reputation,the results manifested that CD-1 steel is appropriate for slicing knives.