What is the minimum bending radius for Q355 structural components in medical equipment during bending?
Answer: It depends on the thickness of the sheet metal. For standard cold-rolled sheets: thickness ≤ 3mm, minimum bending radius R = 0.5t (t is the sheet thickness); 3mm < t ≤ 10mm, R = t; t > 10mm, R = 1.5t. The minimum bending radius for hot-rolled sheets needs to be 50% larger than that for cold-rolled sheets to avoid cracks at the bend. It is recommended that the bending radius for medical equipment structural components be slightly larger than the theoretical minimum to improve structural stability.
Do Q355 precision structural components used in the medical industry require heat treatment?
A: It depends on the performance requirements. High-precision structural components (such as the load-bearing shaft of an operating table or the connecting arm of a CT scanner gantry) require heat treatment (quenching + high-temperature tempering). After treatment, the hardness reaches 220-250 HBW, further improving strength and toughness to meet high load-bearing and high-precision requirements. General structural components (such as equipment bases or trolley frames) do not require heat treatment; hot-rolled/cold-rolled Q355 steel is sufficient to meet performance requirements.
What are the core requirements for the steel mill's quality certificate when the medical industry purchases Q355 steel?
A: Steel mills must provide a formal quality certificate according to GB/T 1591-2018 standard, which must include the following specific information: ① Clearly state the grade (e.g., Q355C), quality level, and delivery condition (hot-rolled/cold-rolled/quenched and tempered); ② Key chemical composition (C≤0.20%, Si≤0.55%, Mn≤1.60%, P≤0.030%, S≤0.030%, C/D/E grades require Al control); ③ Measured values of mechanical properties (yield strength, tensile strength, elongation, impact energy), which must meet the requirements of the corresponding quality level; ④ Inspection results of surface quality and dimensional tolerances; ⑤ Steel mill's inspection stamp, production date, and furnace batch number (the furnace batch number must be traceable, with each furnace batch corresponding to a single batch of steel).
What are the incoming inspection items for Q355 steel in the medical industry, and what standards are implemented? A: Incoming inspection is a full-item inspection. Core items and standards include: ① Visual inspection (visual + calipers): No oxide scale, oil stains, cracks, scratches; dimensional tolerances conform to GB/T 1591; ② Chemical composition analysis (spectroscopy/chemical analysis): Verify C, Mn, Si, P, S, etc., consistent with the quality certificate; ③ Mechanical property testing (tensile, impact, hardness): Performed according to GB/T 228, GB/T 229, GB/T 231; performance indicators not lower than national standard requirements; ④ Surface cleanliness inspection: Performed according to GB/T 8923, reaching Sa2.5 level; ⑤ Non-destructive testing (for thick plates/welded parts): Performed according to GB/T 3323; radiographic/ultrasonic testing reaching Level II or above.
What are the inspection standards and requirements for welding quality of Q355 structural components used in medical equipment? A: The standard is GB 9706.1 and GB/T 3323-2019 "Radiographic Examination of Metal Fusion Welded Joints". The core requirements are: ① Radiographic/Ultrasonic Inspection: The internal defects of the welded joint reach level II or above, with no excessive porosity, slag inclusions, or cracks; ② Visual Inspection: The weld surface is smooth, with no undercut, incomplete penetration, or weld beads, and the weld reinforcement is ≤2mm; ③ Mechanical Property Inspection: The tensile strength of the welded joint is ≥90% of the original material, and the impact energy is ≥80% of the original material; ④ Sealing Inspection (for shells with sealing requirements): There is no leakage in the air pressure/water pressure test.