1. Introduction
and industrial fasteners are mainly manufactured via two core forming technologies: cold heading (cold forging) and hot forging. The forming temperature directly determines product mechanical performance, dimensional tolerance, production cost and applicable scenarios. This guide breaks down the core differences to help engineers and buyers select the right manufacturing process for their fastener projects.
2.
Cold heading processes steel wire rods at room temperature, using high-speed cold heading machines to punch, extrude and form bolt heads, nut blanks without heating raw materials. Raw material: Smooth wire coil (10B21, 4.8/8.8 grade carbon steel, stainless steel wire).
Hot forging heats steel bars to 800–1200℃ recrystallization temperature first, then presses the high-temperature billet with forging dies to form large-size, high-strength fastener blanks. Raw material: Solid steel round bars (45#, 40Cr, 4340 alloy steel).
3.
| 800–1200℃ high temperature | ||
| Small & medium fasteners: M3–M24 standard bolts | Large heavy fasteners: M24–M160 studs, high-pressure bolts | |
| Ultra-precise, consistent size, thin uniform thread allowance | Rough blank tolerance, extra machining required post-forging | |
| High-speed automatic line, thousands of pieces per minute | Low output, single-piece manual feeding, slow cycle | |
4.
-Superior mechanical performance: Unbroken metal fiber improves fatigue resistance, ideal for automotive fasteners (10B21 8.8 grade bolts).
-High precision: Uniform dimensions, consistent thread pitch, less post-processing.
-High automation: Mass production reduces labor cost, stable delivery lead time.
-Clean surface: Little oxidation, zinc plating/Ruspert coating adheres evenly.
-Size restriction: Cannot process bolts above M24 due to equipment tonnage limits.
-Hard material limitation: Hard alloy steel cannot be cold formed without cracking.
-Unlimited size range: Produce super-large studs, anchor bolts, pressure vessel bolts.
-High alloy compatibility: Works with 40Cr, A193 B7, duplex stainless steel for high-temperature industrial use.
-High forming force at high temp: Complex special-shaped forgings can be shaped easily.
-Poor surface quality: Thick oxide scale requires secondary machining.
-Lower fatigue strength: Heating breaks internal metal grain flow.
-Higher cost: Energy consumption for heating, slower production, extra finishing process.
5.
-Standard small & medium bolts: M6–M20 10B21 automotive bolts, fine thread bolts (M20×1.5)
-Standard hex nuts, spring washers, small socket cap screws
-Mass consumer industry: Furniture, construction, machinery general fasteners
-Low to medium strength grades: 4.8, 6.8, 8.8 carbon steel series
-Large heavy-duty fasteners: M30–M120 full thread studs, wind turbine tower bolts
-High-pressure equipment: Oil & gas pipeline bolts, LNG tank studs, ASTM A193 B7 high-temperature bolts
-Special heavy anchor bolts, mining machinery oversized fasteners
-High strength alloy grades: 10.9, 12.9 grade alloy steel, super duplex steel fasteners
6. FAQ
Q1: Can hot-forged bolts reach 12.9 strength grade?
A: Yes, but hot forging only makes blanks. After hot forming, quenching & tempering heat treatment is required to reach 10.9/12.9 grade. Cold heading 10B21 can directly hit 8.8 grade after heat treatment with better fatigue performance.
Q2: Why are cold heading products cheaper for standard bolts?
A: Cold heading runs fully automatic high-speed lines without heating energy cost, fewer secondary processing steps, higher hourly output, which cuts unit cost significantly for large orders.
If you require cold heading or hot end forming processes, Handan Jihao Fasteners can provide you with professional consultation and one-stop service. For ordering and more information, please contact:
WhatsApp+8613111607537
Email:baiyanyun219@gmail.com