difference of steel materials Q235ABCD
difference of steel materials Q235ABCD
Q235 is an extremely common ordinary carbon structural steel. It is one of the most widely used steels and plays an important role in many industrial and civil fields. Q235A, Q235B, Q235C, Q235D is a kind of steel material. “Q” stands for the yield of this material, and “235” refers to the yield value of about 235Mpa.
It has good comprehensive mechanical properties, including a certain degree of strength, good plasticity and toughness, and can withstand a certain degree of tensile, compressive and bending loads.
At the same time, it also has good welding performance, not easy to produce welding defects, porosity, cracks, etc., it also has good cutting and processing performance, and cold bending, hot bending performance, such as in some construction sites used in the steel frame keel, it is made through the cold bending process.
Q235A grade does not do impact; Q235B grade for 20 degrees room temperature impact; Q235C grade is 0 degrees impact; Q235D grade is -20 degrees impact. Do not do the impact test requirements of the lowest, do the impact test, the lower the temperature, the lower the low-temperature brittleness, the better performance; the same temperature, the impact of the attack on the value of the larger, the better performance. Q235ABCD, low-temperature brittleness in order to become better, of which Q235D low-temperature brittleness is the best, the best low-temperature resistance.
Q235ABCD, this four grades, as the grade increases, the carbon and sulfur content requirements are more stringent, the carbon content is slightly reduced. In mechanical properties, the four grades of tensile strength, yield strength and elongation requirements are the same, only mechanical and chemical properties have some differences.
Q235A: carbon content of 0.14%-0.22%, manganese content of 0.30%-0.65%, impurity elements such as sulphur, phosphorus and other loose control;
Q235B: carbon and sulphur content is roughly the same as Q235A, with slightly stricter requirements on the content of impurity elements;
Q235C: more stringent control of sulfur, phosphorus and other impurity elements;
Q235D: sulfur, phosphorus and other impurity element content in all levels of the lowest, to ensure that the low temperature environment has a better toughness.
Q235A is not as tough and strong as other grades at low temperatures because it is not impact tested. It is usually used in occasions that do not require high impact performance, and is widely used in the construction industry to make various building components, such as steel beams, steel columns and roof frames. In general mechanical manufacturing, it is also used to make some parts that are not subject to much force, such as small brackets and housings. At the same time, it is also used in the manufacture of daily necessities, like some simple metal furniture frames.
Q235B is impact tested at 20°C room temperature and is suitable for building structures, bridges, ships, etc. in room temperature environment. Its mechanical properties are better than Q235A, so it is more common in some projects with certain requirements for strength and toughness. It is commonly used in building structures and mechanical parts with high requirements for safety and reliability. In the manufacture of chemical equipment, it is used to make some storage containers and so on. In bridge construction, it is also a commonly used type of steel, capable of withstanding the impact of dynamic loads such as vehicle travelling.
Q235C is capable of impact testing at 0°C. It is suitable for cold regions or structural parts that need to work at lower temperatures, such as cold storage and low temperature containers.
Q235D is capable of impact testing at -20°C, with optimal low-temperature toughness and strength, suitable for projects in extremely cold environments, and commonly used in the manufacture of important structures and equipment with extremely high requirements for quality and safety, such as buildings and piping systems in high-latitude areas, etc. Q235D is able to effectively resist adverse factors such as corrosion by seawater and extremely low temperatures, ensuring the long-term and stable operation of equipment.
The different grades of Q235ABCD are mainly reflected in the differences in the temperature and chemical composition of the impact test, which make them show different performance characteristics at different temperatures and application scenarios. Selection of the appropriate grade of Q235 should be based on specific engineering requirements and environmental conditions.
In the construction of railway track systems, steel made of Q235 is mainly used in those parts where the requirements for strength are relatively low, but good weldability, plasticity and cost-effectiveness are needed.
Track foundation and auxiliary structure
Track bedding plate: Q235 steel can be used to make the bedding plate connecting the sleeper and rail, used to disperse the pressure of the rail and reduce the wear of the sleeper. It is particularly common in general railway and light rail systems.
Rail presses/fastening accessories: Q235B is commonly used to manufacture small structural components such as rail presses, bolts and washers for general fastening systems.
Railway stations and ancillary facilities
Platform steel structure: Platform roofs, handrails, guardrails and other parts are usually made of Q235 because of its sufficient strength and at the same time low cost.
Cargo and storage facilities: Q235 steel is commonly used to build steel frames, steel beams and some auxiliary facilities (e.g., simple racks for storing equipment) for yard warehouses.
Rail transport equipment
Maintenance and track-laying equipment accessories: The frame structure of light rail transport equipment (e.g. certain non-load-bearing parts of track-laying machines and rail hoists) may also be made of Q235.
Accessories for rail transporters/flatcars: Used for the manufacture of certain non-critical components such as connectors or loading platforms.
Other small structural parts
Bolts, nuts, washers: Q235B is commonly used in the manufacture of fasteners for general connections (non-high-strength bolt scenarios).
Baffles and guards: Guards along railway lines, such as trackside baffles or small metal parts for support, are usually made of Q235 steel.
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