significance
The development of human civilization and the progress of society are closely related to metal materials. The Bronze Age and the Iron Age, which emerged after the Stone Age, were marked by the application of metallic materials. Modern, a wide variety of metal materials has become an important material basis for the development of human society.
species
Metal materials are usually classified into ferrous metals, non-ferrous metals, and specialty metallic materials.
1 ferrous metal is also called steel material, including industrial pure iron containing more than 90% of iron, 2% to 4% of carbon containing carbon, carbon steel containing less than 2% carbon, and structural steel, stainless steel and heat resistant for various purposes. Steel, superalloy
Stainless steel, precision alloys, etc. The broad ferrous metals also include chromium, manganese and their alloys.
2 Non-ferrous metals refer to all metals and their alloys except iron, chromium and manganese. They are usually classified into light metals, heavy metals, precious metals, semi-metals, rare metals and rare earth metals. Non-ferrous alloys generally have higher strength and hardness than pure metals, and have large electrical resistance and small temperature coefficient of resistance.
3 special metal materials include structural metal materials and functional metal materials for different purposes. Among them are amorphous metal materials obtained by rapid condensation process, as well as quasi-crystal, microcrystalline, nanocrystalline metal materials, etc.; and special functional alloys such as stealth, hydrogen, superconductivity, shape memory, wear resistance, vibration damping and the like. And metal matrix composite materials.
performance
Generally divided into two categories of process performance and performance. The so-called process performance refers to the performance of metal materials under the specified cold and hot processing conditions during the manufacturing process. The technical performance of metal materials determines its adaptability to the forming process during the manufacturing process. Due to different processing conditions, the required process properties are different, such as casting properties, weldability, forgeability, heat treatment properties, and machinability. The so-called performance refers to the performance of metal parts under the conditions of use, including mechanical properties, physical properties, chemical properties, and the like. The performance of metal materials determines its range of use and service life. In the mechanical manufacturing industry, general mechanical parts are used in normal temperature, normal pressure and very strong corrosive media, and each mechanical part will be subjected to different loads during use. The resistance of metal materials to damage under load is called mechanical properties (also referred to as mechanical properties in the past). The mechanical properties of metal materials are the main basis for the design and selection of parts. The applied load properties are different (such as tensile, compression, torsion, impact, cyclic loading, etc.), and the mechanical properties required for the metal material will also be different. Common mechanical properties include: strength, plasticity, hardness, impact toughness, multiple impact resistance and fatigue limit. Example:
Platinum has good ductility and can be drawn into filaments with a diameter of only 1/5 000 mm; gold has good ductility and can be pressed into sheets having a thickness of only 1/10 000 mm. The difference in properties determines the use of metals.
The utility model provides an electronic igniter, which is characterized in that it is composed of a shell with an ignition port at the left end and a button port on it, an ignition tube connected with the ignition port at the left end of the shell, an ignition device fixedly connected with the button port, and a cable connected with the ignition device. The ignition device is composed of a rectangular shell and a button sliding connected with the upper end of the shell, The utility model is composed of a striker connected with the lower surface of the button, a power generation ceramic block fixedly connected with the bottom of the shell, a thimble connected with the upper surface of the power generation ceramic block, and a spring which is connected with the power generation ceramic block and sheathed outside the thimble. The electronic igniter has the characteristics of simple structure, safe and reliable, convenient operation, no need to use batteries, etc., which is not only economical and environmental protection, but also convenient for wide promotion.
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