Abstract:
PURPOSE: A method of manufacturing sintered gear for transmission, which can reduce manufacturing costs by minimizing post processes is provided to increase the density of the sintered gear and to improve strength. CONSTITUTION: A method of manufacturing sintered gear for transmission comprises the next step. Carbon(C) 0.2 ~ 0.3 wt% is mixed in alloyed powder consisting of chrome(Cr) 1.3 ~ 1.7 wt%, molybdenum(Mo) 0.15 ~ 0.30 wt% and remainder iron(Fe). The pressure is added in the mixed powder and tooth form is given to the mixed powder. The molded materials are sintered in 1200 ~ 1300°C. The sintered materials(1) are rolled between two rolling dies(3,5) in room temperature. The rolled materials are heat-treated.
Abstract:
A coating composition for a sliding member is provided to prevent scuffing caused by a continuous load and heat and to significantly reduce friction and wear. A coating composition for a sliding member comprises: at least one resin material selected from polyamideimide(PAI) resins and polyimide(PI) resins; and at least one solid lubricating agent selected from sulfide, fluorine-containing compounds and graphite, wherein the solid lubricating agent is used in an amount of 1-500 parts by weight based on 100 parts by weight of the resin material. Particular examples of the sulfide include molybdenum disulfide or tungsten disulfide.
Abstract:
본 발명은 탄소 0.2∼0.8 중량% 및 구리 1.0∼5.0 중량%을 포함하고 나머지는 철로 구성되는 저합금 철분말과, 탄소 1.0∼1.3 중량%, 크롬 3.5∼4.2 중량%, 몰리브덴 9.0∼10.0 중량%, 바나듐 1.0∼1.4 중량%, 텅스텐 1.2∼1.8 중량%, 코발트 7.8∼8.5 중량% 및 실리콘 0.5 중량% 이하를 함유하고 나머지는 철로 구성되는 고합금 철분말이 1:1로 혼합된 것을 특징으로 하는 피스톤용 다공질 소결재 인서트 조성물과; 상기 다공질 소결재 인서트 조성물을 금형속에 넣고 링형상의 성형체가 되도록 5∼7kgf/㎠으로 압력을 가하되, 성형체의 밀도는 5.5∼6.5 g/cm 3 가 되도록 하고, 상기 링형상의 성형체를 환원분위기의 소결로에서 소결온도 1050∼1250℃로 30∼60분 동안 소결하여, 기공율이 30∼50 부피%인 다공질의 소결재 인서트로 제조되는 것을 특징으로 하는 피스톤용 다공질 소결재 인서트의 제조 방법을 제공하고자 한 것이다.
Abstract:
PURPOSE: A wear resistant sintered alloy for valve seat is provided which improves wear resistance and formability by containing iron as a principal constituent, carbon, chromium, molybdenum, vanadium, tungsten, silicon, manganese and lead only without cobalt, and a manufacturing method thereof is provided. CONSTITUTION: The method comprises first process of press molding the blended alloy to a surface pressure of 5 to 8 tons/cm¬2 by blending a principal constituent of iron, 0.3 to 0.5 wt.% of carbon, 1.0 to 3.0 wt.% of chromium, 2.0 to 4.0 wt.% of molybdenum, 2.0 to 4.0 wt.% of vanadium, 5.0 to 7.0 wt.% of tungsten, 0.2 to 0.4 wt.% of sulfur, 0.2 to 0.5 wt.% of manganese and 10.0 to 15.0 wt.% of lead; second process of air cooling the sintered alloy after sintering the press molded alloy at a temperature of 1,140 to 1,180 deg.C after finishing the first process; third process of subzero cooling the air cooled sintered alloy to a temperature of -200 to -600 deg.C after finishing the second process; fourth process of impregnating the subzero cooled alloy with lead at a temperature of 450 to 550 deg.C after finishing the third process; and a process of manufacturing the wear resistant sintered alloy for valve seat by passing the lead impregnated alloy through barrel process at a temperature of 450 to 550 deg.C after finishing the fourth process.
Abstract:
PURPOSE: An apparatus for heating cooling water of a diesel engine using PTC elements is provided to prevent a cooling apparatus from being overheated by cutting off a current by rapidly increasing resistance if a temperature of a heating part becomes higher than a predetermined temperature. CONSTITUTION: An apparatus for heating cooling water is formed of a PTC(Positive Temperature Coefficient) heater(10) including a pair of heat sinks(12) and a plurality of PTC elements(11) connected with electrodes(13) respectively in a state that the plurality of PTC elements are inserted into mounting grooves(12a-2) of the heat sinks. The PTC heater has sealing grooves(12a-1,12b-1) formed at an inside combination surface(12a) and an outside cover combination body(12b), and an insert rubber(14) and a sealing rubber(15) installed at the sealing grooves respectively.
Abstract:
PURPOSE: A sintering alloy material composition is provided which has superior properties to an existing sintering alloy material for valve guide by adding a certain amount of boron nitride to an existing iron sintering alloy material, thereby improving abrasion resistance, and adding silicate powder, thereby developing a material having superior machinability. CONSTITUTION: The sintering alloy material composition for a valve guide comprises a main constituent of iron, 1.7 to 2.5 wt.% of carbon, 4.0 to 6.0 wt.% of copper, 0.2 to 0.55 wt.% of tin, 0.15 to 0.4 wt.% of phosphorus, 0.3 to 1.5 wt.% of boron and 0.3 to 2.5 wt.% of silicon, wherein the boron is contained by using 0.5 to 2.0 wt.% of rigid particles of boron nitride alloy powder for the total sintering alloy material composition, and the silicon is contained by using 0.5 to 3.0 wt.% of silicate powder for the total sintering alloy material composition.
Abstract:
본 발명은 자동차 엔진에 있어서, 캠 축의 회전운동을 왕복운동으로 바꾸어 주는 부분인 밸브 태핏(valve tappet)을 제조하는데 사용되는 철계 소결합금에 관한 것으로서, 상세하게는 탄소, 크롬, 몰리브덴, 망간 및 텅스텐 등과 잔부는 철로 구성되는 밸브 태핏용 소결합금에 관한 것이다. 본 발명의 소결합금은 탄화물 및 붕화물이 기지조직에 다량으로 분포되며, 조직이 마르텐사이트(martensite)화 됨으로써 우수한 내마모성 및 내부식성을 지녀 밸브 태핏용 재료로 유용하게 사용될 수 있다.
Abstract:
C 0.6-1.5중량%, Ni 1.0-2.5중량%, Cr 2.0-3.8중량%, Mo 2.8-5.2중량%, Co 2.9-4.7중량%, Nb 0.5-1.5중량%, B 0.6-1.8중량%,Cu 11.0-18.0중량%, Fe 78.6-61.0중량%로 이루어진 소결합금 조성물은 내마모성, 내충격성, 열전도성이 우수하며, 생산원가 측면에서도 저렴하여 자동차 밸브 시이트용 소재로서 유용하다.