These points cannot be ignored in the construction of steel structure workshop Steel Structure Workshop,Steel Frame Workshop,Workshop Steel Structure,Steel Structure Warehouse Workshop Henan Jinming Metal Material Co., Ltd. , https://www.hnjmsteel.com
(1) Density, relative density Density refers to the mass per unit volume of a substance, in short, the ratio of mass to volume, in units of millions of grams per cubic meter (Mg/m3) or Kg/m3 (kg/m3) or g/cm3 (g/cm3). The relative density, also known as the ratio of the density, refers to the ratio of the density of a substance to the density of a reference substance under their respective specified conditions, or to the mass of a volume of material at t1 and an equal volume of reference material at t2. The ratio of the mass under temperature. The commonly used reference substance is distilled water, and it is expressed as Dt1/t2 or t1/t2, which is a non-dimensional amount.
(2) Melting point and freezing point (Melting point, Freezing point) The material in its vapor pressure liquid-solid equilibrium temperature is called the melting point or freezing point. This is due to the regular arrangement of atoms or ions in the solid because of the temperature rise, the thermal motion becomes messy and activated, forming a phenomenon of irregularly arranged liquids, and the opposite process is solidification. The temperature at which the liquid turns into a solid is often referred to as freezing point or freezing point, and the difference from the melting point is that heat is emitted instead of absorbing heat. In fact, the melting point and freezing point of the substance are the same.
(3) Melting range means the temperature range from melting of the substance to melting of the substance as determined by the capillary method.
(4) Crystal point means the temperature at which a liquid changes from a liquid state to a solid state during the cooling process.
(5) Pour point One of the indicators of the nature of liquid petroleum products. The temperature at which a sample is cooled under standard conditions until it starts to stop flowing, that is, the minimum temperature at which the sample can be poured when it is cooled.
(6) Boiling point The temperature at which the liquid is heated by boiling to become a gas. Or the temperature at which the liquid and its vapor are in equilibrium. In general, the lower the boiling point, the greater the volatility.
(7) Boiling range Distilled volume within the temperature range specified in the product standard under standard conditions (1013.25 hPa, 0°C).
(8) Sublimation A phenomenon in which a solid (crystalline) substance is directly converted into a gaseous state without passing through a liquid state. Such as ice, iodine, *, naphthalene, camphor, ***, etc. can be sublimated at different temperatures.
(9) Vaporizing velocity Evaporation refers to the phenomenon of gasification occurring on the surface of a liquid. Evaporation rate, also known as evaporation rate, is generally judged by the boiling point of the solvent. The fundamental factor that determines the evaporation rate is the vapor pressure of the solvent at the temperature, followed by the molecular weight of the solvent.
(10) Vapor pressure Vapor pressure is an abbreviation of saturated vapor pressure. At a certain temperature, the liquid and its vapour reach equilibrium, and the equilibrium pressure at this time changes only due to the nature and temperature of the liquid, which is referred to as the saturated vapour pressure of the liquid at that temperature.
(11) Azeotrope Azeotrope is an azeotropic mixture in which two (or more) liquids form an azeotrope. It refers to a mixed solution in which the gas and liquid phases are completely the same at equilibrium. The corresponding temperature is called azeotropic temperature or azeotropic point.
(12) Refractive index Refractive index is the physical quantity that represents the ratio of light speed of light in two different (isotropic) media. The speed of light varies from medium to medium. When light enters another transparent medium with a different density from a transparent medium, it changes in direction as it changes in speed, so it is called refraction. The ratio of the sine of the angle of incidence of the light to the sinusoidal angle of refraction, or the ratio of the speed of the light through the vacuum and through the medium, is the refractive index. The general expression of the refractive index n is a value at which light enters any medium from air. The index of refraction usually referred to is sodium yellow (D line), measured at tC, so it is expressed as ntD, and as measured at 20C, it is n20D.
(13) Flashing point Flashing point, also known as the flash point, represents one of the indicators of the nature of flammable liquids. Refers to the minimum temperature at which a flammable liquid is heated to the vapor pressure and air mixture on its surface in contact with the flame to produce a flash fire. Flash fire is usually a light blue spark, which is off immediately and cannot continue to burn. Flashing is often a harbinger of a fire. There are open cup method and closed cup method for measuring flash point. Generally, the former is used to determine high flash point liquid and the latter is used to determine low flash point liquid.
(14) Ignition point The ignition point, also called the ignition point, is one of the indicators of the nature of flammable liquids. Refers to the lowest temperature at which a mixture of vapor and air heated by flammable liquids on the surface of the flammable liquid immediately contacts the flame and continues to burn. The flammable liquid has a flash point of 1 to 5°C above the flash point. The lower the flash point, the smaller the difference between the flash point and the flash point.
(15) Spontaneous ignition point The lowest temperature at which a flammable substance can cause ignition without contact with an open flame, and is called the spontaneous ignition point. The lower the autoignition point, the greater the risk of fire. The spontaneous ignition point of the same substance varies with conditions such as pressure, concentration, heat dissipation, and test methods.
(16) Explosive limits When the combustible gas, flammable liquid vapor or combustible solid dust is mixed with air or oxygen at a certain temperature and pressure to reach a certain concentration range, it will explode when it meets the fire source. This certain concentration range is called the explosion limit or the combustion limit. If the composition of the mixture is not within this certain range, then the supply of energy will be greater and no ignition will occur. Vapor or dust mixed with air and reach a certain concentration range, the lowest concentration that encounters the fire will burn or explode is called the lower explosion limit; the highest concentration is called the upper explosion limit. The explosion limit is usually expressed as the volume percentage of vapor in the mixture, that is, % (vol); the dust is expressed in mg/m3 concentration. If the concentration is lower than the lower explosion limit, although the open flame will not explode or burn, because the proportion of air is large, the concentration of combustible vapor and dust is not high; if the concentration is higher than the upper limit of explosion, although there is a large amount of flammable substances, it is missing. The combustion-supporting oxygen, in the absence of air supplements, does not explode for a moment even in the event of an open flame. Flammable solvents have a certain range of explosion. The wider the explosion range, the greater the danger.
(17) Viscosity Viscosity is the internal frictional resistance of a fluid (liquid or gas) in the flow. Its size is determined by the type, temperature, and concentration of the material. Generally referred to as dynamic viscosity, the unit is Pa•s or mPa•s (mPa•s). Viscosity is divided into dynamic viscosity, kinematic viscosity, and relative viscosity. The three are different and cannot be confused. Viscosity can also be measured by coating or coating - 1 cup, its unit is second (s).
(18) Mooney viscosity Mooney viscosity, also known as rotational (Mooney) viscosity, is a value measured with a Mooney viscometer that basically reflects the degree of polymerization and molecular weight of the synthetic rubber. According to the GB 1232 standard, the rotational (Money) viscosity is represented by the symbol Z100°C 1+4. Among them, Z—rotational viscosity value; 1—preheating time is 1 minute; 4—rotation time is 4 minutes; 100° C.—test temperature is 100° C., and it is customary to express Mooney viscosity at ML100° C. 1+4.
(19) Solubility The maximum amount of material dissolved in a given amount of a given solvent at a given temperature and pressure is called solubility. The solubility of a solid or liquid substance is generally expressed in grams of the dissolved substance in 100 g of solvent. The solubility of a gas solute is usually expressed in milliliters of dissolved gas per liter of solvent.
(20) Solubility parameter Solubility parameter, also known as solubility parameter, is a measure of intermolecular force. The effect of bringing together molecules can be called cohesive energy. The cohesive energy per unit volume is called the cohesive energy density (CED), and the square root of the CED (CED)1/2 is defined as the solubility parameter, code-named δ or SP.
(21) Surface tension and surface energy The attraction of the molecules in the liquid causes the molecules on the surface to act inwardly. This force causes the liquid to shrink its surface area as much as possible to form parallel surfaces. Force, called surface tension. Or it is the mutual traction between the two adjacent parts of the liquid surface, which is a manifestation of the molecular force. The unit of surface tension is N/m. The size of the surface tension is related to the nature, purity and temperature of the liquid. Surface tension multiplied by the surface area is the surface energy. The greater the surface tension, the greater the surface area and the greater the surface energy it has.
(22) Specific heat capacity The amount of heat that is required to increase by 1K per kilogram of substance is called the specific heat capacity, and the unit is kJ/(kg•K). Under the same pressure condition, the heat absorbed when the temperature rises by 1K is called constant pressure specific heat capacity.
(23) Thermal conductivity In the past, thermal conductivity was referred to as thermal conductivity or thermal conductivity and reflected the thermal conductivity of a material. That is, two parallel planes with a distance of 1 cm and an area of ​​1 cm 2 are taken perpendicular to the thermal conduction direction inside the object. If the temperature difference between the two planes is 1K, then the heat transferred from one plane to the other within ls is defined as the substance. The thermal conductivity of the unit is W/(m•K).
(24) Water content Water contained in a substance, but does not include crystal water and associated water. The mass of the sample is usually expressed as a percentage of the mass of the sample after it has lost water.
(25) Water absorption is a measure of the degree of water absorption of a substance. Refers to the percentage of mass increased by immersing the substance in water for a certain period of time at a certain temperature.
(26) Ash Ash, also known as burning residue, refers to the residue of oxides and salts formed by the mineral components after evaporation and burning, expressed as a percentage.
(27) Needle penetration The penetration is represented by the depth of a standard needle that penetrates into the asphalt sample vertically under a certain load, time and temperature, and the unit is 1/10mm. Unless otherwise specified, the combined weight of the standard needle, the pin connecting rod and the additional weight is 100±0.1g, the temperature is 25°C, and the time is 5s. The greater the penetration, the softer it is, that is, the smaller the consistency. On the contrary, it means the harder, that is, the greater the consistency.
(28) Hardness Hardness is the resistance of the material to external forces such as embossing and scratches. According to the test method, there are Shore hardness, Brinell hardness, Rockwell hardness, Mohs hardness, Barcol hardness, Vichers hardness, and the like. The hardness value is related to the type of hardness tester. In the commonly used hardness tester, the Shore hardness tester has a simple structure and is suitable for production inspection. Shore hardness testers can be divided into Type A, Type C, and Type D. Type A is used to measure soft rubber, and Models C and D are used to measure semi-rigid and hard rubber.
(29) Aniline point (A.P.) The aniline point is the lowest temperature at which an equal volume of petroleum alkane and aniline dissolve each other to indicate the content of paraffinic saturated hydrocarbons. The aniline point is related to the chemical composition. The higher the aniline point is, the more alkane content is. The lower the aniline point is, the more aromatic content is.
(30)Volume resistivity (Volume resistivity), also called volume resistance, volume resistivity, is an important indicator to characterize the dielectric properties of dielectric or insulating materials. Indicates the resistance of the 1cm3 dielectric to the leakage current in Ω•m or Ω•cm. The greater the volume resistivity, the better the insulation performance.
(31)Oil absorption The amount of oil required when the absolute surface of the particles of a given quality (fill) is completely wetted by the oil.
(32) Acid value The acid value, also known as the acid value, is an indicator of organic matter. It is the number of milligrams of potassium hydroxide (KOH) required to neutralize the free acid in the nonvolatile matter of 1 g of organic matter. That is, mgKOH/g.
(33) Hydroxyl value The number of milligrams of potassium hydroxide (KOH) corresponding to the hydroxyl groups in a 1 g sample is expressed in mgKOH/g.
(34) Iodine value An indicator of the degree of unsaturation of organic matter. It is the mass percentage of iodine absorbed by 1g sample. The higher the degree of unsaturation, the greater the iodine value.
(35) Epoxy value Epoxy value is an equivalent number of epoxy groups contained in 100 g of epoxy resin. The larger the epoxy value, the smaller the molecular weight and the lower the viscosity.
(36) Epoxy equivalent The epoxy equivalent represents the molecular weight of the corresponding resin for each epoxy group. .
(37) HLB value (HLB value) HLB is the abbreviation of Hydrophile-Lipophile-Balance, which is used to measure the relative intensity of the polar and non-polar groups in the surfactant molecule. If the polar group is stronger, its HLB value is larger and the hydrophilicity is stronger; if the non-polar group is longer, its HLB value is smaller and the hydrophilicity is worse.
(38) Critical micell concentration Critical micelle concentration, also known as critical micelle concentration, is abbreviated as CMC. The concentration range of the emulsifier solution is mutated and is called the critical micelle concentration of the emulsifier. After the emulsion system reached the critical micelle concentration, many emulsifier molecules aggregated to form micelles. The unit of CMC is mol/L.
(39) Degree Baum'e The value given by Baume's meter in a special indexing method in a glass tube float is called Baume's degree, and the symbol is °B'e. Used to indirectly give the density of the liquid.
(40)Solid content Solid content, also known as non-volatile content, total solid content (TS), means the ratio of the mass of the sample after heating at a certain temperature to the mass of the sample, expressed as a percentage.
(41) Surface-active agent Also known as surfactants, substances that can significantly alter the surface tension of liquids or the interfacial tension of two phases. Or substances that can strongly adsorb on the surface of other substances or accumulate on the surface of the solution and reduce the surface tension of the liquid or solid.
(42) Relative humitity A method of expressing humidity is the ratio of absolute humidity to saturated absolute humidity under the same conditions (at the same temperature and pressure), ie under the same conditions, in air (or other gas). The ratio of the actual water vapor content to the saturated water vapor mass. Usually expressed as a percentage.
(43) Apparent density Previously known as bulk density, bulk density, pseudo density, apparent density, and mass per unit volume (including voids).
(44) Isomer compounds have the same molecular formula, but different structures and properties are called isomeric. Compounds that can undergo isomerism are called isomers, or isomers.
(45) Relative Molecular Mass (abbreviated as molecular weight) refers to the ratio of the average mass of a molecule or a specific unit of a substance to the mass of a 10 6 C atom of a nuclides (1/12). The symbol is Mr.
(46) Number average molecular weight The polymer is composed of homologous mixtures with the same chemical composition and different degree of polymerization, ie, a mixture of polymers with different molecular chain lengths. The average molecular weight is often used to characterize the size of the molecule. According to the statistical average of the number of molecules, it is called the number average molecular weight and the symbol is (ˉMn).
(47)Degree of polymerization (degree of polymerization) The number of segments that make up the molecular chain of a polymer is called the degree of polymerization, codenamed n or DP, and can be used as a measure of the size of the polymer.
(48) Molecular weight distribution Molecular weight distribution is due to the fact that the molecular weight has statistical properties as well as polydispersity, ie molecular weight distribution. The same average molecular weight will have different molecular weight distributions, exhibiting different properties.
(49) Homopolymer A polymer that is polymerized from the same monomer to form a chain repeat called a homopolymer.
(50) Copolymer A polymer formed by the polymerization of two or more monomers or monomers and polymers, known as a copolymer, which is divided into block copolymers, random copolymers, and Regulating copolymers, graft copolymers, etc.
(51) Graft copolymer A copolymer in which some of the atoms of the polymer backbone are attached to a side chain of a polymer segment different in chemical structure from the main chain, called a graft copolymer, Graft neoprene, SBS graft copolymer.
(52) Prepolymer A polymer with a low molecular weight (below 1500) between the monomer and the final polymer, also known as an oligomer, an oligomer (Oligmer). Polymers composed of a few links, such as dimers, trimers, tetramers, or mixtures of these oligomers.
(53) Glass transition temperature The approximate midpoint of a narrow temperature range in which an amorphous or semi-crystalline polymer transitions from a viscous or highly elastic state to a glassy state (or vice versa), known as vitrification. Temperature, usually expressed as Tg, is an indicator of heat resistance.
(54) Brittle temperature A measure of the low-temperature properties of a polymer. When a hammer with a certain energy impacts the sample, the temperature at which the sample cracks at 50% is called brittle temperature. Called crisp breakpoints.
(55)Heat deflection temperature under load (Heat deflection temperature under load) A measure of the heat resistance of a polymer is to immerse a polymer sample in a suitable heat transfer medium at a constant rate of temperature rise. Under the bending load, the temperature at which the bending deformation of the specimen reaches the specified value is measured, which is the heat distortion temperature, abbreviated to HDT.
The cost of the steel structure factory building is low, and the construction efficiency is high. It only needs to complete the basic design, and the construction can be completed immediately, and the factory building can be put into use quickly. However, when building a factory, we still have to pay special attention to the following points.
simple design
Different from other buildings, the steel structure factory building should still have a simple shape, generally designed as a rectangle, so that it is more convenient to use later and can also ensure the internal space. The layout can be carried out according to the terrain of the site, and attention must be paid to the specific design location of the workshop and whether there is a certain functional area division. Generally, the terrain slope of the factory building should not be greater than 5%, and the hilly slope should not be greater than 40%. Therefore, the construction should be carried out according to the local conditions, and the slope should be reasonable.
Construction location confirmation
As far as possible, the factory building should avoid locations such as earthquake faults, especially some locations prone to mudslides and landslides are not suitable for building factory buildings. If it is a valuable mining area, ancient tomb, etc., try not to build factories, etc. Before the construction of the factory building, it is necessary to do a good on-site inspection. If the local area is not suitable for the construction of the factory building, try to choose another place, so as to avoid the need to relocate the factory building later, which will be more troublesome and waste time and construction costs.
Reserved land for expansion
Steel structure workshops are very easy to expand, because with the increase in later construction requirements, many workshops may need to be expanded. Therefore, at the beginning of construction, a place for expansion should be reserved. At least the process requirements, transportation requirements, and whether there are other plant constructions should be considered.
Pay attention to construction inspection Steel Structure Workshop and Steel Structure Warehouse are relatively easy to construct and construct, so it is still necessary to pay attention to the need for safety personnel to inspect the site, and report in time if there are some installation problems. Moreover, after the construction is completed, there must be a construction inspection, and the stability of the plant must be ensured, so as not to affect the later use of the plant.
It is only necessary to select the appropriate materials for the construction of the steel structure factory building, and choose a suitable construction location, then basically the construction of the factory building can be completed immediately, and the factory building can also be quickly put into later use.
Chemical and plastic terms
In the quality index of raw materials, there are often some terms that are encountered to accurately understand its meaning and help to better grasp the performance of raw materials. List some commonly used terms.