摘要:
A ceramic sintered body comprising TiB.sub.2 as the principal component, 0.5 to 30 wt. % of SiC and 2 to 40 wt. % of ZrO.sub.2. In some cases ZrO.sub.2 includes stabilizers for tetragonal crystal, such as Y.sub.2 O.sub.3, MgO or CeO.sub.2. The sintered body has a dense structure where TiB.sub.2, ZrO.sub.2 and SiC uniformly disperse. ZrO.sub.2 is located at the grain boundary of TiB.sub.2, and inhibits the grain growth of TiB.sub.2 as well as improves the strength of the sintered body by binding it to TiB.sub.2 strongly. SiC is located not only at the grain boundary but also on the inside of both grains. Since the contract of SiC during cooling process of the sintered body is less than TiB.sub.2 and ZrO.sub.2, compressive stress is produced in SiC and around thereof. The sintered body is remarkably strengthened by the residual compressive stress, and simultaneously, the high fracture toughness is also achieved.
摘要:
An orifice plate for liquid injection made of plate-shaped stainless steel, wherein an orifice is formed by shearing, is characterized in that the average crystal grain size of the stainless steel is 3 μm or less. The thickness of the plate-shaped stainless steel is 1.2 mm or less, and preferably 0.1 mm or less. The aspect ratio of the orifices is 0.8 or lower. The orifices are formed orthogonal to the plate surface, or slanted by 50° or at smaller angles. The plate-shaped stainless steel has a composition containing C, Mn, and Si.
摘要:
A wire rod or a steel wire of a bamboo nano-structure, whose mean grain diameter in a C-direction section is 200 nm or smaller, is prepared by applying a hot or warm working and additionally applying a cold working to a steel and next, by performing a forging, by a tool or a die such as cold pressure production, to a section, of a desired, limited site, other than a section parallel to an L-direction, an equiaxed nano-structure, whose mean grain diameter is 200 nm or smaller, is formed in this site. As a typical example of a formed article, there is enumerated a high strength micro screw in which a shaft outer diameter is 1.6 mm or smaller, a surface layer part of a head part recess has equiaxed nano-structure and a hardness Hv≧300, and a screw main body portion has bamboo nano-structure and a hardness Hv≧250.
摘要:
A high strength phosphorus-containing steel having fine texture free from the problem of embrittlement by positively using the presence of P, which is a carbon steel having an average ferritic grain diameter of 3 &mgr;m or less and containing from 0.04 to 0.1% by mass of P, wherein the volume fraction of P segregated in the grain boundary accounts for 0.3 or less in case the grain boundary is covered by a P layer 1 nm in thickness.
摘要:
A method of rolling with a flattened-shaped caliber in a 1st pass and subsequently roiling with a square-shaped caliber in a 2nd pass In a caliber rolling of two or more continuous passes. The rolling is performed with a caliber which sets the ratio of the minor axis (2A01) of a 1st pass flattened to a material opposite side dimension (2A0) to A01/A0≦0.75 and the ratio of a 2nd pass vertical diagonal dimension 2As1 to the major axis 2B1 of a material after the 1st pass to As1/B1≦0.75 to introduce the large strain into the material. Thus, the effect of the distribution of strain introduced into the material in the 1st pass on the distribution of strain and the shape of the next pass is made clear so that the large strain can be introduced into the entire cross sectional are of the material, particularly at the center of the material.
摘要:
A method of producing a ultra fine grain steel made of ferrite having a mean grain size of not larger that 3 &mgr;m as the base phase, after ingoting raw materials, by austenitizing the ingot by heating it to a temperature of at least an Ac 3 point, then, applying compression working of a reduction ratio of at least 50% at a temperature of from an Ae 3 point or lower to an Ar 3 point −150° C., or at a temperature of at least 550° C., and thereafter, cooling, wherein the strain rate as compression working is in the range of from 0.001 to 10/second.
摘要:
The invention provides an ultra-fine grain steel comprising fine ferrite grains as oriented at random and surrounded by large angle grain boundaries. The steel comprises fine ferrite grains having a mean grain size of not larger and 3.0 &mgr;m and surrounded by large angle grain boundaries having an misorientation not smaller than 15°.
摘要:
An orifice plate for liquid injection made of plate-shaped stainless steel, wherein an orifice is formed by shearing, is characterized in that the average crystal grain size of the stainless steel is 3 μm or less. The thickness of the plate-shaped stainless steel is 1.2 mm or less, and preferably 0.1 mm or less. The aspect ratio of the orifices is 0.8 or lower. The orifices are formed orthogonal to the plate surface, or slanted by 50° or at smaller angles. The plate-shaped stainless steel has a composition containing C, Mn, and Si.
摘要:
The invention presents a new warm control rolling method, in consideration of processing heat generation, as a method of stably manufacturing ultrafine crystal steel of 3 microns to 1 micron or less, without any limitation in pass interval or strain speed, being a rolling method of manufacturing steel mainly composed of fine ferrite particle texture with average ferrite grain size of 3 μm or less, in which, in the rolling process of one pass or more wherein the rolling temperature range is a temperature region of 350° C. to 800° C., the material temperature upon start of rolling of each rolling process does not exceed the maximum temperature of 800° C., and the material temperature during rolling and right after final rolling (within 1 second) is not lower than 350° C., temperature Tx-out right after rolling in each rolling process (within 1 second) is not higher than the temperature that is higher than rolling entry temperature Tx-in by 100° C. and the material temperature right after rolling (within 1 second) is not lower than the temperature that is lower than the temperature right before rolling by 100° C.
摘要:
A wire rod or a steel wire of a bamboonano-stricture, whose mean grain diameter in a C-direction section is 200 nm or smaller, is prepared by applying a hot or warm working and additionally applying a cold working to a steel and next, by performing a forging, by a tool or a die such as cold pressure production, to a section, of a desired, limited site, other than a section parallel to an L-direction, an equiaxed nano-structure, whose mean grain diameter is 200 nm or smaller, is formed in this site. As a typical example of a formed article, there is enumerated a screw, and there is enumerated a high strength micro screw in which a shaft outer diameter is 1.6 mm or smaller, a surface layer part of a head part recess is the equiaxed nano-structure and a hardness HV≧300, and a screw main body portion is the bamboo nano-structure and a hardness Hv≧250. A constituent composition is a carbon steel of C