Answers

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  What are the differences between pipeline steel pipes and ordinary steel pipes?

  The main differences between pipeline pipes and ordinary steel pipes lie in their materials, application scenarios, and classification standards.
  Firstly, in terms of materials, pipeline pipes typically use high-strength, high-toughness, high-quality low-alloy structural steel, such as X70 and X80 steel grades. This makes their corrosion resistance significantly superior to that of ordinary steel pipes, which are mostly made of ordinary carbon steel.
  Secondly, in terms of applications, pipeline pipes, due to their superior performance, are widely used in key areas such as urban gas supply, oil and natural gas transportation, and water conservancy projects; while ordinary steel pipes are more commonly used in building structures, the manufacture and support of mechanical components, etc.

  
  

  Performance and Manufacturing Process Comparison
  Pipeline Steel Pipes:
  Typical Material: X42-X80 grade steel (e.g., X60 indicates a yield strength ≥414 MPa), requiring a drop hammer tear test (DWTT) to ensure low-temperature brittleness resistance.
  Working Pressure: Typically ≥10 MPa (e.g., the West-East Gas Pipeline design pressure is 12 MPa), requiring a hydrostatic test (test pressure is 1.5 times the design pressure).
  Standard anti-corrosion coating (e.g., 3LPE anti-corrosion layer thickness ≥2.5 mm); some require the addition of corrosion inhibitors.
  
  Ordinary Steel Pipes: Pressure-bearing capacity is mostly <6 MPa, no mandatory anti-corrosion requirements, and only some galvanized pipes (zinc layer thickness ≥40 μm) are used for rust prevention.
  
  Differences in Manufacturing Processes
  Pipeline Steel Pipes: Material is mostly Q195-Q345B, with a lower limit of yield strength of only 195 MPa, and no mandatory low-temperature toughness requirements. For high-frequency resistance welding (HFW) or submerged arc welding (SAW), the weld seams require 100% ultrasonic testing.
  
  For ordinary steel pipes, ordinary arc welding or cold rolling is used, and the weld seam inspection rate is low (e.g., 5% random sampling).

  
  
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  The difference between 2B stainless steel and brushed stainless steel？

  2B stainless steel is the base surface state after cold rolling. It is made through the process of "cold rolling → annealing and pickling → leveling". The surface has a uniform silver-gray misty appearance, a smooth and delicate feel, and can vaguely reflect objects. The passivation film is complete and has a high degree of flatness. It is the original substrate for most surface treatments, retaining the basic properties of stainless steel itself, without any additional processing textures.
  
  The brushed board uses 2B board as the base material and is directionally polished with abrasive materials such as 320-grit sandpaper to form a continuous and uniform filamentous texture (including straight filaments, snowflake sand, etc.). The surface has a matte frosted texture, which can effectively cover up minor scratches and fingerprints. Its processing requires multiple steps such as "degreasing → cleaning → drying → film application", which makes the process more complex and the cost 20%-50% higher than that of 2B boards.
  
  The core advantages of 2B boards are cost-effectiveness and versatility. They have a smooth and clean surface, better corrosion resistance, and are suitable for scenarios with high requirements for surface flatness. Whether it's for food processing equipment liners, chemical pipelines, medical device components, or substrates requiring further polishing and electroplating, 2B sheets can handle it all.
  
  Brushed sheets, on the other hand, emphasize a balance between decoration and practicality, offering a high-end texture that is wear-resistant, fingerprint-resistant, and provides a soft, non-glaring visual effect. It is widely used in high-frequency contact scenarios such as building decoration, home appliance panels, and furniture accessories, and is especially suitable for spaces that pursue an industrial style or low-key texture.

  
  
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  What are the differences between round bar and carbon structural bar?

  1. Different concepts: Round bar refers to solid, long steel bars with a circular cross-section. Its specifications are expressed in diameter, in millimeters (mm), such as "50mm," which means round bar with a diameter of 50 millimeters.
  High-quality carbon structural steel is abbreviated as carbon structural bar. Specifically, it refers to steel with a carbon content of less than 0.08%. Compared to ordinary carbon steel, it has superior quality, strict chemical composition requirements, and guaranteed mechanical performance indicators. It is a high-quality carbon structural steel with lower levels of harmful impurities such as phosphorus and sulfur.
  
  2. Different shapes: Round bar has a smooth, round shape without patterns or ribs, while carbon structural steel has patterns or ribs on its surface. This results in weaker adhesion between round bar and concrete and stronger adhesion between carbon structural steel and concrete.
  
  3. Different compositions: Round steel (Grade 1 steel) belongs to ordinary low-carbon steel, while carbon structural steel is mostly alloy steel.
  
  4. Different specifications: Round bar refers to solid, long steel bars with a circular cross-section. Its specifications are expressed in diameter, in millimeters (mm), such as "50mm" indicating a round bar with a diameter of 50 millimeters. High-quality carbon structural steel is abbreviated as carbon steel. Specifically, it means its carbon content is less than 0.08%.
  
  5. Different Uses: Round steel with a carbon content between 0.65% and 1.35% can achieve high hardness and high wear resistance after heat treatment, and is mainly used to manufacture various tools, cutting tools, molds, and measuring instruments (see tool steel).
  The uses of carbon steel are indicated by its grade, with lower numbers indicating lower carbon content. Low-carbon steel includes carbon steel grades such as 08F and 10F, which have good plasticity and toughness, and are often used to manufacture parts requiring a hard and wear-resistant surface while maintaining good core integrity after surface heat treatment.