Typical MOQ
10pieces
Subject to product and material review.
Conditions
MOQ is typically 10 pieces, subject to product, material and manufacturing-route review.
431 Hex Bolts — ASTM F593
Material431Change · 45 grades
- Material
- 431 · UNS S43100 · Stainless steel 431
- Material focus
- High strength after hardening & tempering
- Common applications
- Pump shafts · valve assemblies · fasteners
- Main elementslimits · wt.%
- Cr 15–17%
- Ni 1.5–2.5%
- C 0.12–0.20%
Standards & threads
Finished boltASTM F593Alloy Group 6 · 431 · H · inch series
Specify the finished hardened-and-tempered condition and size-dependent acceptance. Scope: nominal 1/4–1-1/2 in.; this is not a metric specification. Identify the exact alloy, condition and edition.
A supplier QT800 / QT900 bar label does not automatically establish F593 H bolt compliance.
Raw material specificationASTM A276/A276M / ASTM A479/A479MUNS S43100
S43100 · stainless bar
Select the stock-form specification and required condition. These are bar specifications, not finished-bolt strength classes.
Dimensions · metricISO 4014 / ISO 4017Coarse pitch · partial-thread bolts / full-thread hex screws
Dimensions · inchASME B18.2.1Inch hex bolts / hex cap screws
Select the bolt or cap-screw pattern, head dimensions and thread length. Hex and heavy hex are different choices.
Threads · metricISO 261 / ISO 965-1Metric M · pitch plan and tolerance system
Threads · UNC / UNFASME B1.1Unified inch · coarse / fine series
State diameter, TPI, series and external class: e.g. 1/2-13 UNC-2A or 1/2-20 UNF-2A. Select 2A / 3A with the mating-thread fit; UNC and UNF do not mate.
Heat treatment / conditionHardened + tempered · QT800
Reference specimen: Bar
Reference condition from material data. The ordered condition is agreed in your quotation.
Sources & editions Reviewed 2026-10-19
Historical samples support the stated grade coverage. The ordered edition controls the full requirements.
Preview your dimensions
Example dimensions, not a stock size.
Simplified right-hand thread appearance. No tolerance, fit or standard compliance is simulated.
Head dimensions · optional
Head proportions are illustrative: s = 1.5d, k = 0.625d. They are not standard-table values and will not be submitted as specified dimensions.
Quality documents
Heat number traceability
Every delivery traceable by heat number
Mechanical testing
Included with every delivery
Thread inspection
GO / NO-GO gauging · sampled inspection
Methods, sampling and acceptance criteria follow the agreed specification. PMI, third-party inspection and additional records are agreed separately.
Before production and at delivery
During quotation, a redacted certificate from a previous order can show the document format and recorded tests. It is a historical example, not certification of this product or a new order. Shipment documents must correspond to the material and batch actually supplied.
How to read a historical certificate sample ↗Prepare your enquiry
Send a drawing and quantity.
No drawing? Use these details.
- Size
- d × L Diameter × under-head length
- Quantity
- Pieces Required quantity per size
- Thread
- Metric / UNC / UNF Pitch or TPI + thread class
- Coverage
- Full / Partial For partial, include threaded length
Full material checklist
Treatment condition
S43100 and the exact hardened / tempered condition required.
Avoids silently adopting QT800 from a reference table.
Strength and toughness
Required values, test conditions and relevant bolt section.
Defines the mechanical balance for the actual connection.
Lot evidence
Treatment record, hardness and specified strength / toughness reports.
Links the supplied part to the required condition instead of a generic bar description.
Commercial terms
Indicative terms; confirmed in your quotation.
Sample review
~20days
Freight, import duties and taxes are separate.
Conditions
Samples are typically reviewed on an approximately 20-day basis. BYBOLT may cover agreed sample manufacturing; buyer freight, import duties and taxes remain separate.
Production review
25–35days
Urgent requirements can be discussed.
Conditions
Regular production is commonly reviewed on a 25–35 day basis. Urgent requirements can be discussed against the complete specification.
Typical deposit
30%
T/T or LianLian. Balance before dispatch.
Conditions
Payment can be arranged by T/T or LianLian. A typical order uses a 30% deposit, with the balance completed before dispatch.
Technical help
Does a QT800 or QT900 bar label establish F593 H bolt compliance?
Those labels describe a supplier’s bar-condition basis. F593 Group 6 H has its own finished-fastener requirements. Specify the required final treatment and tests, and verify that the completed bolt evidence supports the selected route.
Which properties matter alongside hardness for 431 bolts?
State the required strength and any toughness acceptance for the actual bolt diameter and service. Keep these requirements linked to the final hardened-and-tempered condition and the finished-lot sampling plan.
Read a thread designation Metric / UNC / UNF
M12 × 1.75–6g12 mm diameter · 1.75 mm pitch · external class 6g
1/2-13 UNC-2A1/2 inch · 13 TPI · coarse · external class 2A
1/2-20 UNF-2A1/2 inch · 20 TPI · fine · external class 2A
Examples explain designations, not available sizes. Specify fine pitch explicitly. UNC and UNF do not mate; full or partial threading is a separate choice.
Thread classes and inspection ↗Related material guides
Download the PO and receiving checklist (PDF)
Guides for your enquiry
Specify your 431 bolt
Send a drawing or add your dimensions and quantity.
Continue to enquiry ↗
Combine several products in one enquiry
431 hex boltsEnquire ↗