Turbine bolt alloy steel bar (YB/T158-1999) Introduction
Turbine bolt alloy steel bar, also known as turbine rotor head bolt steel bar, is an important material widely used in the power industry. It is mainly used as a connecting bolt in turbines, generators and other high-speed and heavy-duty rotors. YB/T158-1999, the national standard for turbine bolt alloy steel bar (hereinafter referred to as alloy steel bar) was issued and announced by the Technical Supervision Bureau in April, 1999. This standard stipulates the applicable range, technical requirements, test methods, inspection rules, inspection rules and marks for turbine bolt alloy steel bar.
The applicable range of turbine bolt alloy steel bar is: the diameter of 8~36mm, the elongation is not less than 22%, the yield strength is not less than 220Mpa, the tensile strength is not less than 420Mpa, the carbon content is 0.19~0.46%, the hardness is HRC21~32 and the impact test is not lower than 40J/cm2.
The technical requirements of turbine bolt alloy steel bar include chemical composition, tensile properties, dimensional tolerances and surface quality.
1. Chemical composition
The chemical composition of the turbine bolt alloy steel bar includes the following components: Carbon (C): 0.19-0.46%; Silicon (Si): 0.20-0.35%; Manganese (Mn): 0.50-1.00%; Chromium (Cr): 0.80-1.20%; Molybdenum (Mo): 0.25-0.60%; Vanadium (V): 0.15-0.30%; Phosphorus (P): 0.03%; Sulphur (S): 0.03%.
2. Tensile properties
Tensile properties include tensile strength, yield strength, elongation, impact energy and hardness.
Tensile strength: not less than 420Mpa; Yield strength: not lower than 220Mpa; Elongation: not less than 22%; Impact energy: not lower than 40J/cm2; Hardness: not above HRC32.
3. Dimensional tolerance
The dimensional tolerances of turbine bolt alloy steel bar include diameter, out-of-roundness, out-of-straightness and end face angle. The tolerance of the diameter is 0~+1.5mm, the tolerance of the out-of-roundness is ≤3mm/m, the tolerance of the out-of-straightness is ≤1.5mm/m, and the tolerance of the end face angle is ≤4°.
4. Surface quality
The surface quality of the turbine bolt alloy steel bar includes surface appearance, surface defects and surface nondestructive testing. The surface shall be free of dirt and oil, there shall be no obvious mechanical damage, and no heavy corrosion, cutting chips and nitrate. Internal defects such as porosity and inclusions are also prohibited.
Test methods
The test methods of turbine bolt alloy steel bar include chemical composition analysis, tensile properties, dimensional tolerances and surface quality tests.
Chemical composition analysis: according to the national standard GB223, using the inert gas fusion analysis method.
Tensile properties: according to the national standard GB/T 228-2010.
Dimensional tolerances: according to the national standard GB/T 9105, measured by a digital vernier caliper.
Surface quality test: according to the national standard GB/T 6391-2012, no evidence of flaws is required.
Inspection rules, marks and packaging
Inspection rules
The national standard YB/T 158-1999 stipulates the inspection rules for turbine bolt alloy steel bar. The inspection must be carried out strictly in accordance with the regulations to inspect the material and product quality.
Mark
The external marking of turbine bolt alloy steel bar is divided into: raw material marking, factory marking and certificate of inspection marking.
Raw material marking: The supplier shall mark the number, heat treatment number, grade, manufacturer name, batch number, etc. on the raw material.
Factory marking: The factory shall mark the heat treatment number and factory name on the side of the product.
Inspection certificate marking: The manufacturer shall mark the heat treatment number, grade, manufacturer name, batch number, etc.on the contents of the inspection certificate.
Packaging
The packaging of turbine bolt alloy steel bar is divided into two types: common packaging and special packaging. Common packaging includes gunny bag packaging and steel drum packaging. Special packaging includes wooden boxes, wooden barrels and special containers for air, sea and rail transportation.
Conclusion
Turbine bolt alloy steel bar is an important material widely used in the power industry. YB/T158-1999 is the national standard for turbine bolt alloy steel bar. It stipulates the applicable range, technical requirements, test methods, inspection rules, inspection rules and marks for turbine bolt alloy steel bar. The applicable range is: the diameter is 8~36mm, the elongation is not less than 22%, the yield strength is not lower than 220Mpa, the tensile strength is not lower than 420Mpa, the carbon content is 0.19~0.46%, the hardness is HRC21~32 and the impact test is not lower than 40J/cm2.
The technical requirements include chemical composition, tensile properties, dimensional tolerances and surface quality. Test methods include chemical composition analysis, tensile properties, dimensional tolerances and surface quality tests.
Inspection rules, marks and packaging are also included in the national standard YB/T 158-1999. Raw material marking, factory marking and certificate of inspection marking should be marked on the products. The packaging of turbine bolt alloy steel bar is common packaging and special packaging.
Turbine bolt alloy steel bar must meet the requirements of the national standard YB/T 158-1999. With strict requirements, it can effectively guarantee the quality of turbine bolt alloy steel bar and ensure the safety of turbines, generators and other high-speed and heavy-duty rotors.
