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Bolts · ASTM A193 Grade B7; ASME B18.31.3 and ASME B1.1

A4 (316) Stainless Steel Inch Fully Threaded Rod, ASTM A193 B7

Mechanical properties, corrosion behaviour and the full dimensional range for this grade.

A4 Stainless Steel Inch Fully Threaded Rod, ASTM A193 B7 are supplied to ISO 3506 group A4 (316 / 1.4401), commonly supplied A4-80. Corrosion behaviour is superior, including marine and chloride environments, the material is largely non-magnetic, and the usable service range is approx. -200 °C to +400 °C, subject to the property class and the joint. In practice this grade is specified for marine, coastal and chemical applications.

Grade
ISO 3506 group A4 (316 / 1.4401), commonly supplied A4-80
Corrosion resistance
Superior, including marine and chloride environments
Magnetic response
Largely non-magnetic
Service temperature
approx. -200 °C to +400 °C, subject to the property class and the joint

Property values are typical for the grade. Certified mechanical test data is available on request for production orders.

A4 (316) Stainless Steel Inch Fully Threaded Rod, ASTM A193 B7 reference image

A4 Stainless Steel (ISO 3506 group A4 (316 / 1.4401), commonly supplied A4-80) is specified for marine, coastal and chemical applications. When inch fully threaded rod, astm a193 b7 are specified in this grade, the dimensions remain per ASTM A193 Grade B7; ASME B18.31.3 and ASME B1.1; the material determines corrosion behavior (superior, including marine and chloride environments) and the service temperature range (approx. -200 °C to +400 °C, subject to the property class and the joint). Both are covered below with the size table.

Why Choose A4 Stainless Steel for Inch Fully Threaded Rod, ASTM A193 B7

Specified for marine, coastal and chemical applications. For inch fully threaded rod, astm a193 b7, this matters when superior, including marine and chloride environments is the primary requirement.

Mechanical & Physical Properties

Grade designationISO 3506 group A4 (316 / 1.4401), commonly supplied A4-80
Magnetic responseLargely non-magnetic
Service temperatureapprox. -200 °C to +400 °C, subject to the property class and the joint
Corrosion characteristicSuperior, including marine and chloride environments

Galvanic & Galling Considerations

Two important notes for stainless inch fully threaded rod, astm a193 b7: (1) stainless can gall on stainless threads under load — use a thread lubricant or anti-galling compound, especially for M6 and below; (2) when joined to aluminum or galvanized steel, stainless can drive galvanic corrosion of the less-noble metal in wet service — isolate with a coating or sleeve where appropriate.

Comparable Grades

For Inch Fully Threaded Rod, ASTM A193 B7, the alternative stainless grade is A2 (304). A2 (304) suits general indoor and outdoor service; A4 (316) adds molybdenum for marine and chloride environments. Where higher strength matters more than corrosion, switch to plated alloy-steel class 8.8 or 10.9.

Using Stainless Fasteners in Aluminum

Stainless steel is more noble than aluminum, so in the presence of an electrolyte — rain, condensation, salt spray — the aluminum becomes the anode and corrodes at the joint. The effect is driven by the area ratio: a small stainless fastener in a large aluminum section is normally acceptable, while a large stainless fastener in thin aluminum is not. Where the joint is wet, isolate the two metals with a coated or nylon washer and a sealant, or specify an aluminum or coated fastener instead.

Sizes of Inch Fully Threaded Rod, ASTM A193 B7 Available in A4 Stainless Steel

Nominal sizeThread seriesStandard lengths (ft)Minimum tensile (ksi)Minimum yield (ksi)Elongation minimum (%)Finish optionsReference standard
1/4-20UNC / optional UNF or 8UN3 / 6 / 1212510516plain / yellow-zinc / black-oxide / hot-dip-galvanizedASTM A193 Grade B7; ASME B18.31.3 and ASME B1.1
3/8-16UNC / optional UNF or 8UN3 / 6 / 1212510516plain / yellow-zinc / black-oxide / hot-dip-galvanizedASTM A193 Grade B7; ASME B18.31.3 and ASME B1.1
1/2-13UNC / optional UNF or 8UN3 / 6 / 1212510516plain / yellow-zinc / black-oxide / hot-dip-galvanizedASTM A193 Grade B7; ASME B18.31.3 and ASME B1.1
3/4-10UNC / optional UNF or 8UN3 / 6 / 1212510516plain / yellow-zinc / black-oxide / hot-dip-galvanizedASTM A193 Grade B7; ASME B18.31.3 and ASME B1.1
1-8UNC / optional UNF or 8UN3 / 6 / 1212510516plain / yellow-zinc / black-oxide / hot-dip-galvanizedASTM A193 Grade B7; ASME B18.31.3 and ASME B1.1
1-1/4-7UNC / optional UNF or 8UN3 / 6 / 1212510516plain / yellow-zinc / black-oxide / hot-dip-galvanizedASTM A193 Grade B7; ASME B18.31.3 and ASME B1.1

Technical Drawing

Customize the parameters below — every spec field is editable, and the drawing redraws to match the values you choose. Changing the size will snap the other fields to that size's standard values; you can then override any individual value.

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Specification
Business Information

Dimensions & Specifications (ASTM A193 Grade B7; ASME B18.31.3 and ASME B1.1)

Nominal sizeThread seriesStandard lengths (ft)Minimum tensile (ksi)Minimum yield (ksi)Elongation minimum (%)Finish optionsReference standard
1/4-20UNC / optional UNF or 8UN3 / 6 / 1212510516plain / yellow-zinc / black-oxide / hot-dip-galvanizedASTM A193 Grade B7; ASME B18.31.3 and ASME B1.1
3/8-16UNC / optional UNF or 8UN3 / 6 / 1212510516plain / yellow-zinc / black-oxide / hot-dip-galvanizedASTM A193 Grade B7; ASME B18.31.3 and ASME B1.1
1/2-13UNC / optional UNF or 8UN3 / 6 / 1212510516plain / yellow-zinc / black-oxide / hot-dip-galvanizedASTM A193 Grade B7; ASME B18.31.3 and ASME B1.1
3/4-10UNC / optional UNF or 8UN3 / 6 / 1212510516plain / yellow-zinc / black-oxide / hot-dip-galvanizedASTM A193 Grade B7; ASME B18.31.3 and ASME B1.1
1-8UNC / optional UNF or 8UN3 / 6 / 1212510516plain / yellow-zinc / black-oxide / hot-dip-galvanizedASTM A193 Grade B7; ASME B18.31.3 and ASME B1.1
1-1/4-7UNC / optional UNF or 8UN3 / 6 / 1212510516plain / yellow-zinc / black-oxide / hot-dip-galvanizedASTM A193 Grade B7; ASME B18.31.3 and ASME B1.1

Applications & Industries

The sectors that buy Inch Fully Threaded Rod to ASTM A193 Grade B7; ASME B18.31.3 and ASME B1.1, and the duty each one buys them for. Stocked from 1/4-20 to 1-1/4-7 (screw size).

Industries that specify Inch Fully Threaded Rod

  • Refinery maintenance Bolting packages exposed to heat, pressure and hydrocarbon service.
  • Power generation Large flanged joints and equipment supports using inch specifications.
  • Structural plant Tie rods and hold-down assemblies requiring ASTM A193 Grade B7 material.
  • Pressure vessels High-strength threaded rod and studs in flanged pressure equipment.
  • Plant & machine installation Anchoring and levelling machines onto bases and frames.
  • Steel fabrication Hanger rods, tie rods and made-to-length threaded assemblies.

Typical applications

  • assembling flanged joints where a full-length thread is required
  • selecting ASTM A193 Grade B7 strength and a compatible finish
  • cutting standard 3, 6 or 12 ft stock to the required stud length
  • providing a high-strength inch threaded member for nuts at both ends
  • made-to-length assemblies cut and threaded on site
  • clamping a joint from both ends where a headed bolt will not fit

Service conditions to specify against

Marine and coastal
Available in A4 (316) stainless for chloride exposure — coastal structures, pool halls, water treatment and deck hardware, where A2 will eventually pit.
High load
Supplied in ISO 898-1 property classes, so the joint can be designed to a stated proof load and tightened to a calculated torque rather than by feel.
Exterior structural
Hot-dip galvanised options for external steelwork; allow for the thicker coating in the mating thread.

Where to use something else

  • Do not mix coatings and nut materials without checking thread compatibility and service temperature.
  • Not for a joint that must be tightened from one side only — there is no head to hold.

Full application guide: where Inch Fully Threaded Rod are used, how to specify them, and the cases they are wrong for

Inside the plant

Manufactured in our own plant

This part is cold-formed, threaded, heat-treated and finished in-house. The stages below are where its class and finish are actually decided.

  1. Wire rod feeding into a cold heading machine
    01

    Cold heading

    Wire rod is drawn to size and cold-formed into blanks. Forming rather than cutting keeps the grain flow continuous around the head, which is where a bolt is most likely to fail.

    Head dimensions and under-head radius checked at set-up and per shift.

  2. Thread rolling machine producing bolt threads
    02

    Thread rolling

    Threads are rolled between hardened dies rather than cut. Rolled threads are stronger in fatigue than cut threads and hold pitch and flank angle far more consistently across a batch.

    Go / no-go ring gauges to ISO 965 tolerance class 6g.

  3. Baskets of bolts staged for heat treatment
    03

    Heat treatment

    Quench-and-temper brings carbon and alloy steel to the property class ordered — 8.8, 10.9 or 12.9 — with the furnace charge tracked so a finished lot can be traced back to it.

    Core hardness and tensile tested per lot to ISO 898-1.

  4. Zinc plated bolts in a treatment basket
    04

    Surface treatment

    Zinc, zinc-nickel, hot-dip galvanizing, black oxide, phosphate and Dacromet, selected against the service environment rather than against the price list.

    Coating thickness and neutral salt spray hours to ISO 9227.

Frequently Asked Questions

Can A4 Stainless Steel Inch Fully Threaded Rod, ASTM A193 B7 be used with aluminum?

Yes, but stainless drives mild galvanic corrosion of aluminum in wet service — isolate with a coating, sleeve or paint, or accept the trade-off if the joint is dry and indoor.

What's the service temperature limit for A4 Stainless Steel?

The practical service range is approx. -200 °C to +400 °C, subject to the property class and the joint.

Can A4 Stainless Steel replace plated alloy steel structurally?

Only at the standard strength classes — A2-70 / A4-80 are roughly equivalent to class 7 steel; A4-100 reaches class 8.8. For class 10.9 or 12.9 strength, plated alloy steel is required.

Are A4 Stainless Steel Inch Fully Threaded Rod, ASTM A193 B7 magnetic?

A4 Stainless Steel Inch Fully Threaded Rod, ASTM A193 B7 are largely non-magnetic.

How do I request a quotation?

Use the technical drawing on this page to pick the exact configuration, then submit it with the quote form. We respond within one business day.