Hot Bend vs Cold Bend – Key Differences

Cold Bend – Bend at ambient temperature using mechanical force
✅ Faster, no heat distortion
⚠ Risk: Wall thinning & ovality if radius is tight
Hot Bend – Heat tube (induction/furnace) before bending
✅ Lower stress, more uniform thickness, ideal for tight radius & hard materials
⚠ Requires temperature control, PWHT, oxidation protection
📐 Rule of Thumb
• Cold Bend: R/D ≥ 1.3
• Hot Bend: R/D < 1.3, thick wall, low ductility, alloy steels
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📏 Extrados Thickness Check (UTM)
1️⃣ Reference Thickness
• Measure straight tube wall (before bending) → baseline tthckness of straight tube.
2️⃣ Measurement Points
• Readings at Apex (180°), ±30°, ±60°, ±90°
• Record extrados (12 o’clock) thickness
• Optional: check intrados (6 o’clock) & neutral sides (3 & 9 o’clock)
3️⃣ Acceptance Criteria
• Wall ≥ design minimum thickness
• Ovality ≤ 10%
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🔎 At Agon Pacific, every bend is controlled by ASME & OEM tolerances for ovality, wall thinning, and hardness. With UTM verification, we ensure bending precision and reliable service life.
✅ Precision bending = Longer service life
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