431 Long-shank flange bolts
ISO 4162ASTM A276 / ASTM A479
The long grip and integral bearing flange give 431 bolts two distinct interfaces to control. Hardenable stainless strength for loaded mechanical parts must be paired with the required shank length, flange footprint and final condition.
- MOQ
- 100PCS
- Samples · typical
- ~20 days
- Production · typical
- 25–35 days
- Heat treatment
- Annealed / hardened and tempered
EN 10204 3.1 MTC + heat-number traceability
Which standard is on your order?
Raw Material Specifications
Finished-Bolt Specifications
Threads · Metric
Threads · Inch
Dimension Reference
Heat Treatment
Hardened and temperedHardening forms the load-bearing martensitic structure, then tempering adjusts hardness and toughness to the specified final condition.
What we can make in 431
Flanged head
Use on deep mounting brackets and thick equipment stacks where a wide head seat distributes the clamp load. Check the flange diameter against casting recesses and nearby ribs before specifying a larger head.
Extended grip
The extended plain grip can span spacers and thick components while the thread engages beyond them. Match grip length to the assembled stack so the nut can reach its seat without stopping at the thread runout.
- Head
- Integral flange
- Shank
- Extended plain grip
- Length basis
- Under flange
- Threads
- Metric · UNC · UNF · UNJ
- Final condition
- Annealed · hardened and tempered
- Inspection
- Thread gauges · Head and shank dimensions
Manufacturing route
CNC machining suits samples and small lots. Cold heading or hot forging is selected for volume production according to alloy formability, head section and size.
Heat treatment & final condition
Hardening and tempering set the final hardness and toughness. Finish dimensions are checked after heat treatment.
Finished geometry
Head geometry, bearing face, shank and thread fit are checked after the final machining and thermal operations.
Where 431 fits — and what matters
Industrial Machinery & Automation
Machine frames and positioning fixtures431 long-shank flange bolts span thick spacers or mounting sections in machine frames and positioning fixtures, combining an extended grip with a flange bearing face. Alignment, operating cycles and replacement access define the working interface.
Automotive & EV Manufacturing Equipment
Assembly fixtures and test-rig frames431 long-shank flange bolts span thick spacers or mounting sections in assembly fixtures and test-rig frames, combining an extended grip with a flange bearing face. Repeated tooling changes require consistent seating and repeatable assembly dimensions.
Pumps, Valves & OEM
Actuator mounts and pump baseplates431 long-shank flange bolts span thick spacers or mounting sections in actuator mounts and pump baseplates, combining an extended grip with a flange bearing face. Repeated maintenance makes fit, engagement and access part of the component specification.
Same long-shank flange bolt. Different material priorities.
431 material data316L
Molybdenum-bearing stainless performance in wet equipment.
- Connection priority
- Grip tension and distributed bearing at the flange
- Washdown and retained cleaner
- Cleaner concentration, rinse quality and deposits determine the exposure in covered joints. The low-carbon designation does not independently establish a fastener strength class. Include liquid retained at the extended grip and the covered surface under the flange in the exposure description.
17-4 PH
Aging-controlled strength and hardness.
- Connection priority
- Grip tension and distributed bearing at the flange
- H900 versus H1150
- The aging condition changes the balance of strength, hardness and toughness. A replacement part needs the specified H condition, especially where contact wear and shock load occur together.
Inconel 625
Solid-solution strength and resistance to aggressive process liquids.
- Connection priority
- Grip tension and distributed bearing at the flange
- Annealed or solution-annealed 625
- The delivery condition affects strength and high-temperature response. Keep the specified condition with the component’s mechanical acceptance; 718-style aging is not the strengthening route for 625. Include liquid retained at the extended grip and the covered surface under the flange in the exposure description.
From drawing to documented delivery
- 01Drawing & BOMForm, dimensions and quantity
- 02Material & formingGrade, heat and manufacturing route
- 03Final inspectionGeometry, threads and ordered tests
- 04Documents & dispatchLot records and identified packing
Order documents
- Material identity
- UNS S43100 · heat number · ordered condition
- Final-part acceptance
- Hardness and mechanical acceptance after hardening and tempering.
- Dimensional record
- Thread gauges · Head and shank dimensions
- Traceability
- EN 10204 3.1 material certificate · production lot · identified packing
Build your 431 long-shank flange bolt enquiry
Questions about 431 long-shank flange bolts
Which dimensions keep the flange and long grip working together?
The flange seat fixes one end of the stack; plain grip and runout fix where the threaded section begins. Specify both against the actual stack thickness so the nut tightens on the parts rather than reaching the end of usable thread.