431 Stud, nut & washer sets
ASME B18.31.2ASTM A276 / ASTM A479
431 stud, nut and washer sets carry the connection from tensile member to bearing surface. Hardenable stainless strength for loaded mechanical parts must be matched by suitable nut engagement and washer bearing strength.
- 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-Component 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
Stud
Include both washers when calculating the clamped stack and usable stud projection. Their thickness can change the stud length needed to engage both nuts.
Nuts
Pair the nut grade, proof load and thread fit with the stud for the intended clamp load. Heavy-hex nuts also need enough radial clearance for the installation socket.
Washers
Use washers to provide the specified bearing footprint or replaceable seating surface. Bore clearance must accommodate the stud, while thickness must support the opening beneath the washer.
- Grade pairing
- Stud + two nuts + washers
- Grade pairing
- Metric · UNC · UNF · 8UN · UNJ
- Grade pairing
- Component-by-component grades
- Grade pairing
- Heat and batch identification
- Final condition
- Annealed · hardened and tempered
- Inspection
- Component count · Mating thread fit · Individual dimensions
Manufacturing route
Studs, nuts and washers are manufactured and inspected as separate components before the specified quantities are packed as a set.
Heat treatment & final condition
Hardening and tempering set the final hardness and toughness. Finish dimensions are checked after heat treatment.
Finished geometry
Thread engagement, nut pattern and component grades are checked together. Each component retains its heat or batch identity in the set documentation.
Where 431 fits — and what matters
Industrial Machinery & Automation
Machine housings and service covers431 stud, nut & washer sets bring the studs, mating nuts and specified bearing washers together for machine housings and service covers. The washer stack is included in the required usable stud length. Alignment, operating cycles and replacement access define the working interface.
Automotive & EV Manufacturing Equipment
Test-equipment housings431 stud, nut & washer sets bring the studs, mating nuts and specified bearing washers together for test-equipment housings. The washer stack is included in the required usable stud length. Repeated tooling changes require consistent seating and repeatable assembly dimensions.
Pumps, Valves & OEM
Pump casings and valve bonnets431 stud, nut & washer sets bring the studs, mating nuts and specified bearing washers together for pump casings and valve bonnets. The washer stack is included in the required usable stud length. Repeated maintenance makes fit, engagement and access part of the component specification.
Same stud, nut & washer set. Different material priorities.
431 material data316L
Molybdenum-bearing stainless performance in wet equipment.
- Connection priority
- Stud tension, nut engagement and washer bearing
- 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 stud–nut threads and both washer-bearing interfaces in the exposure description.
17-4 PH
Aging-controlled strength and hardness.
- Connection priority
- Stud tension, nut engagement and washer bearing
- 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
- Stud tension, nut engagement and washer bearing
- 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 stud–nut threads and both washer-bearing interfaces 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
- Component count · Mating thread fit · Individual dimensions
- Traceability
- EN 10204 3.1 material certificate · production lot · identified packing
Build your 431 stud, nut & washer set enquiry
Questions about 431 stud, nut & washer sets
Can all components be accepted from the stud certificate?
Each component has its own job and material lot. The nut needs thread and strength acceptance, and the washer needs bearing geometry and the ordered condition; retain those records with the stud’s documentation.