Bolts working temperature above 350 ℃ should choose to use heat-resistant steel. Regulating valve bolt steel heat-resistant steel are: low-alloy pearlite heat-resistant steel, high chromium martensitic stainless steel, austenitic stainless steel, iron-nickel-based and nickel-based alloy heat-resistant steel. Stainless steel is both heat-resistant steel, but also corrosion-resistant steel. (1) low-alloy pearlite heat-resistant steel low-alloy pearlite heat-resistant steel can be used at higher temperatures. Chromium molybdenum steel may be selected for bolts having a working temperature below 480 ° C, and chrome molybdenum vanadium steel for working temperatures below 540 ° C. These two types of valve materials in the state of quenched and tempered good short-term use performance, long-term use in the normalizing and tempering has better anti-relaxation properties. Chromium molybdenum vanadium steel after normalizing and tempering, low impact toughness at room temperature, the long-lasting gap sensitivity at 540 ℃, lasting strength decreased. (2) Martensitic stainless steel Martensitic stainless steel bolts containing 12% -17% chromium have better anti-slack performance, higher permanent plasticity and lower notch sensitivity. In addition to the material control valve toughness and thermal strength is better, but also has good damping properties and a smaller linear expansion coefficient, can resist atmospheric and seawater environment corrosion. Martensitic stainless steel bolts for impact load and corrosive media environmental conditions. In the highest operating temperature does not exceed 600 ℃, although its strength is lower than austenitic stainless steel, but still have considerable strength. But martensitic stainless steel low temperature performance is poor. In the environment below 0 ℃ below, the toughness of the material will be lost, there is cold brittle phenomenon. (3) Austenitic stainless steel Austenitic 18-8 stainless steel bolt with good corrosion resistance and high temperature mechanical properties, can be used at 600 ℃ high temperature. And with good low temperature performance, butterfly valve at low temperatures can still maintain a considerable strength. However, the disadvantage is that the yield strength of the material is low and its mechanical properties can not be improved by heat treatment. The austenite precipitation hardening stainless steel is the heat treatment process, through the aging treatment to produce precipitation hardening, precipitation of dispersed carbide and intermetallic compounds, thereby enhancing the strength, while still maintaining the original stainless steel corrosion resistance and good original anti-oxidation Sex, this bolt at 650 ℃ below the use of anti-relaxation performance is more stable, but its high alloy content, heat treatment process is more complex, the price of the material is more expensive. (4) iron-nickel-based alloys and nickel-based alloys Operating temperature above 570 ℃ bolts can choose iron-nickel-based or nickel-based alloys. Control valve materials such as cobalt, with particularly good high temperature performance. Such as the United States waspalog nickel-based alloy can work below 760 ℃; M252 nickel-based alloy can be used to 840 ℃, Cr14Ni25Mo iron-nickel alloy can also be used to 650 ℃; China's production of high-temperature alloys can also be used as high-temperature bolt steel.
The Dock Leveler is an inclined bridge built between the storage platform and the freight car, which is widely used in docks, platforms and warehouses. For forklift trucks to load and unload.
Designed to China JB/T9229 -2013, Australia AS3990, AS3000, America ANSI MH-30.9 -2007. Extensive load bearing cycle testing conducted to prove perdurability. Design confirmed through the latest computer generated finite element analysis. Deck features narrowly spaced support beams (max 200mm) for superior structural integrity. High tensile reinforced anti-slip steel checker plate load lip offers added strength and the smoothest transition between chamfered lip edge and trailer floor.
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Marco Lift (Ningbo) Co., Ltd. , https://www.marcolifttables.com