1: Castability (castability): Refers to the ability of a metal material to obtain a qualified casting by casting. Castability mainly includes fluidity, shrinkage and segregation. Liquidity refers to the ability of liquid metal to fill molds. Shrinkage refers to the degree of volume shrinkage when the castings are solidified. Segregation refers to the fact that metal has a chemical composition and inhomogeneity in the interior of the metal due to successive differences in the process of cooling and solidification. .
2: malleability: Refers to the ability of a metal material to change shape without cracking during pressure processing. It includes processes such as hammer forging, rolling, drawing, extrusion, etc. in hot or cold state. The malleability is mainly related to the chemical composition of the metal material.
3: Machinability (machinability, machinability): Refers to the degree of difficulty for a metal material to be a qualified part after being cut by a tool. Machinability is usually measured by the surface roughness of the workpiece after machining, the allowable cutting speed and the degree of wear of the tool. It is related to many factors such as chemical composition, mechanical properties, thermal conductivity, and work hardening degree of metal materials. Hardness and toughness are generally used as rough judgments of cutting workability. In general, the higher the hardness of metal materials is, the harder it is to cut. Although the hardness is not high, the toughness is large and cutting is difficult.
4: Weldability (weldability): Refers to the adaptability of metal materials to welding processes. Mainly refers to the degree of difficulty in obtaining high quality welded joints under certain welding conditions. It includes two aspects: First, the combination of properties, that is, in a certain welding process conditions, a certain metal to form the sensitivity of welding defects, the second is the use of performance, that is, in a certain welding process conditions, a certain degree of metal welding Applicability of joints to use requirements.
5: Heat treatment
(1): Annealing: A heat treatment process in which a metal material is heated to a suitable temperature for a certain period of time and then slowly cooled. Common annealing processes include recrystallization annealing, stress relief annealing, spheroidizing annealing, and full annealing. The purpose of annealing: mainly to reduce the hardness of metal materials, improve the plasticity, in order to facilitate cutting or pressure processing, reduce residual stress, improve the homogenization of the organization and composition, or prepare the organization for the later heat treatment.
(2) Normalizing: A heat treatment process in which steel or steel is heated to Ac3 or Acm (temperature above the critical point of the steel) and maintained at a temperature of 30 to 50°C for a suitable time and then cooled in still air. The purpose of normalizing is mainly to improve the mechanical properties of low-carbon steel, improve the machinability, refine the grains, eliminate the defects of the structure, and prepare the microstructure for the subsequent heat treatment.
(3) Quenching: Refers to heating the steel to a temperature above Ac3 or Ac1 (the temperature at the lower critical point of the steel) for a certain period of time, and then obtaining the martensite (or bainite) at an appropriate cooling rate. Heat treatment process of the organization. Common quenching techniques include salt bath quenching, martensitic quenching, bainite austempering, surface quenching and partial quenching. The purpose of quenching: to make the steel to obtain the required martensite structure, improve the hardness, strength and wear resistance of the workpiece, and make preparations for the later heat treatment.
(4) Tempering: refers to the heat treatment process after the steel is hardened and then heated to a temperature below Ac1, held for a certain period of time, and then cooled to room temperature. Common tempering processes include: low temperature tempering, medium temperature tempering, high temperature tempering, and multiple tempering. The purpose of tempering: Mainly to eliminate the stress generated during the quenching of steel, so that the steel has high hardness and wear resistance, and has the required plasticity and toughness.
(5): Conditioning: refers to the compound heat treatment process of quenching and tempering steel or steel parts. Steel used for quenching and tempering is called quenched and tempered steel. It generally refers to medium carbon structural steel and medium carbon alloy structural steel.
(6) Chemical heat treatment refers to heat treatment process in which the metal or alloy workpiece is kept in a temperature-sensitive active medium to allow one or more elements to penetrate into its surface layer to change its chemical composition, structure and properties. Common chemical heat treatment processes include carburizing, nitriding, carbonitriding, aluminizing, boronizing, and the like. The purpose of chemical heat treatment: mainly to improve the steel surface hardness, wear resistance, corrosion resistance, fatigue strength and oxidation resistance.
(7):Solution treatment: The alloy is heated to a high temperature single-phase zone and maintained at a constant temperature, so that the excess phase is fully dissolved into the solid solution and rapidly cooled to obtain a heat treatment process of the supersaturated solid solution. The purpose of solution treatment is mainly to improve the plasticity and toughness of steel and alloys, and to prepare for precipitation hardening.
(8): Precipitation hardening (precipitation hardening): A heat treatment process in which a metal in a supersaturated solid solution has a segregation region of solute atoms and/or a dissolvable particle is dispersedly distributed in the matrix to cause hardening. If austenite precipitated stainless steel is subjected to precipitation hardening treatment at 400-500°C or 700-800°C after solution treatment or after cold working, high strength can be obtained.
(9): Aging treatment: Refers to the heat treatment process of the alloy workpiece after the solution treatment, cold plastic deformation or casting, forging, placed at a higher temperature or room temperature, its performance, shape, size change with time. If the aging process is used to heat the workpiece to a higher temperature and perform aging treatment for a longer period of time, it is called artificial aging treatment. If the workpiece is stored at room temperature or under natural conditions for a long period of time, it is called natural aging. Aging treatment. The purpose of aging treatment is to eliminate the internal stress of the workpiece, stabilize the structure and size, and improve the mechanical properties.
(10): Hardenability: It refers to the characteristics of determining the hardened depth and hardness distribution of steel under the specified conditions. The hardenability of steel is good and bad, and it is usually expressed as the depth of hardened layer. The greater the depth of the hardened layer, the better the hardenability of the steel. The hardenability of steel mainly depends on its chemical composition, especially the alloying elements and grain size that contain hardenability, heating temperature and holding time. The hardenability of a good steel, steel can be obtained throughout the entire section of the uniform mechanical properties and quenching stress can be selected steel quenching agent to reduce deformation and cracking.
(11): critical diameter (critical quench-through diameter): The critical diameter is the maximum diameter at which the core gets all martensite or 50% martensite after the steel is quenched in some medium, and the criticality of some steels. The diameter can generally be obtained by the hardenability test in oil or water.
(12): Secondary hardening: Some ferro-alloys (such as high-speed steel) must be tempered several times before further increasing their hardness. This hardening phenomenon, known as secondary hardening, is due to the precipitation of special carbides and/or due to the transformation of austenite into martensite or bainite.
(13) Temper brittleness: refers to the embrittlement phenomenon that the quenched steel is tempered at certain temperature ranges or slowly cooled from the tempering temperature through the temperature range. Temper brittleness can be divided into the first temper brittleness and the second temper brittleness. The first temper brittleness, also known as irreversible temper brittleness, occurs mainly when the tempering temperature is between 250 and 400 °C. After reheating brittleness disappears, it repeats tempering in this section and no brittleness occurs. The second type of tempering occurs. Brittleness, also known as reversible temper brittleness, occurs at a temperature of 400 to 650°C. When reheating brittleness disappears, it should be rapidly cooled. It cannot stay in the range of 400 to 650°C for a long time or slow cooling. Otherwise, catalytic phenomena will occur again. The occurrence of temper brittleness is related to the alloying elements contained in the steel. For example, manganese, chromium, silicon and nickel tend to have temper brittleness, while molybdenum and tungsten tend to weaken temper brittleness.
2: malleability: Refers to the ability of a metal material to change shape without cracking during pressure processing. It includes processes such as hammer forging, rolling, drawing, extrusion, etc. in hot or cold state. The malleability is mainly related to the chemical composition of the metal material.
3: Machinability (machinability, machinability): Refers to the degree of difficulty for a metal material to be a qualified part after being cut by a tool. Machinability is usually measured by the surface roughness of the workpiece after machining, the allowable cutting speed and the degree of wear of the tool. It is related to many factors such as chemical composition, mechanical properties, thermal conductivity, and work hardening degree of metal materials. Hardness and toughness are generally used as rough judgments of cutting workability. In general, the higher the hardness of metal materials is, the harder it is to cut. Although the hardness is not high, the toughness is large and cutting is difficult.
4: Weldability (weldability): Refers to the adaptability of metal materials to welding processes. Mainly refers to the degree of difficulty in obtaining high quality welded joints under certain welding conditions. It includes two aspects: First, the combination of properties, that is, in a certain welding process conditions, a certain metal to form the sensitivity of welding defects, the second is the use of performance, that is, in a certain welding process conditions, a certain degree of metal welding Applicability of joints to use requirements.
5: Heat treatment
(1): Annealing: A heat treatment process in which a metal material is heated to a suitable temperature for a certain period of time and then slowly cooled. Common annealing processes include recrystallization annealing, stress relief annealing, spheroidizing annealing, and full annealing. The purpose of annealing: mainly to reduce the hardness of metal materials, improve the plasticity, in order to facilitate cutting or pressure processing, reduce residual stress, improve the homogenization of the organization and composition, or prepare the organization for the later heat treatment.
(2) Normalizing: A heat treatment process in which steel or steel is heated to Ac3 or Acm (temperature above the critical point of the steel) and maintained at a temperature of 30 to 50°C for a suitable time and then cooled in still air. The purpose of normalizing is mainly to improve the mechanical properties of low-carbon steel, improve the machinability, refine the grains, eliminate the defects of the structure, and prepare the microstructure for the subsequent heat treatment.
(3) Quenching: Refers to heating the steel to a temperature above Ac3 or Ac1 (the temperature at the lower critical point of the steel) for a certain period of time, and then obtaining the martensite (or bainite) at an appropriate cooling rate. Heat treatment process of the organization. Common quenching techniques include salt bath quenching, martensitic quenching, bainite austempering, surface quenching and partial quenching. The purpose of quenching: to make the steel to obtain the required martensite structure, improve the hardness, strength and wear resistance of the workpiece, and make preparations for the later heat treatment.
(4) Tempering: refers to the heat treatment process after the steel is hardened and then heated to a temperature below Ac1, held for a certain period of time, and then cooled to room temperature. Common tempering processes include: low temperature tempering, medium temperature tempering, high temperature tempering, and multiple tempering. The purpose of tempering: Mainly to eliminate the stress generated during the quenching of steel, so that the steel has high hardness and wear resistance, and has the required plasticity and toughness.
(5): Conditioning: refers to the compound heat treatment process of quenching and tempering steel or steel parts. Steel used for quenching and tempering is called quenched and tempered steel. It generally refers to medium carbon structural steel and medium carbon alloy structural steel.
(6) Chemical heat treatment refers to heat treatment process in which the metal or alloy workpiece is kept in a temperature-sensitive active medium to allow one or more elements to penetrate into its surface layer to change its chemical composition, structure and properties. Common chemical heat treatment processes include carburizing, nitriding, carbonitriding, aluminizing, boronizing, and the like. The purpose of chemical heat treatment: mainly to improve the steel surface hardness, wear resistance, corrosion resistance, fatigue strength and oxidation resistance.
(7):Solution treatment: The alloy is heated to a high temperature single-phase zone and maintained at a constant temperature, so that the excess phase is fully dissolved into the solid solution and rapidly cooled to obtain a heat treatment process of the supersaturated solid solution. The purpose of solution treatment is mainly to improve the plasticity and toughness of steel and alloys, and to prepare for precipitation hardening.
(8): Precipitation hardening (precipitation hardening): A heat treatment process in which a metal in a supersaturated solid solution has a segregation region of solute atoms and/or a dissolvable particle is dispersedly distributed in the matrix to cause hardening. If austenite precipitated stainless steel is subjected to precipitation hardening treatment at 400-500°C or 700-800°C after solution treatment or after cold working, high strength can be obtained.
(9): Aging treatment: Refers to the heat treatment process of the alloy workpiece after the solution treatment, cold plastic deformation or casting, forging, placed at a higher temperature or room temperature, its performance, shape, size change with time. If the aging process is used to heat the workpiece to a higher temperature and perform aging treatment for a longer period of time, it is called artificial aging treatment. If the workpiece is stored at room temperature or under natural conditions for a long period of time, it is called natural aging. Aging treatment. The purpose of aging treatment is to eliminate the internal stress of the workpiece, stabilize the structure and size, and improve the mechanical properties.
(10): Hardenability: It refers to the characteristics of determining the hardened depth and hardness distribution of steel under the specified conditions. The hardenability of steel is good and bad, and it is usually expressed as the depth of hardened layer. The greater the depth of the hardened layer, the better the hardenability of the steel. The hardenability of steel mainly depends on its chemical composition, especially the alloying elements and grain size that contain hardenability, heating temperature and holding time. The hardenability of a good steel, steel can be obtained throughout the entire section of the uniform mechanical properties and quenching stress can be selected steel quenching agent to reduce deformation and cracking.
(11): critical diameter (critical quench-through diameter): The critical diameter is the maximum diameter at which the core gets all martensite or 50% martensite after the steel is quenched in some medium, and the criticality of some steels. The diameter can generally be obtained by the hardenability test in oil or water.
(12): Secondary hardening: Some ferro-alloys (such as high-speed steel) must be tempered several times before further increasing their hardness. This hardening phenomenon, known as secondary hardening, is due to the precipitation of special carbides and/or due to the transformation of austenite into martensite or bainite.
(13) Temper brittleness: refers to the embrittlement phenomenon that the quenched steel is tempered at certain temperature ranges or slowly cooled from the tempering temperature through the temperature range. Temper brittleness can be divided into the first temper brittleness and the second temper brittleness. The first temper brittleness, also known as irreversible temper brittleness, occurs mainly when the tempering temperature is between 250 and 400 °C. After reheating brittleness disappears, it repeats tempering in this section and no brittleness occurs. The second type of tempering occurs. Brittleness, also known as reversible temper brittleness, occurs at a temperature of 400 to 650°C. When reheating brittleness disappears, it should be rapidly cooled. It cannot stay in the range of 400 to 650°C for a long time or slow cooling. Otherwise, catalytic phenomena will occur again. The occurrence of temper brittleness is related to the alloying elements contained in the steel. For example, manganese, chromium, silicon and nickel tend to have temper brittleness, while molybdenum and tungsten tend to weaken temper brittleness.