What material grade does Duplex 31803 Socket Cap Screws use?

Duplex 31803 Socket Cap Screws are manufactured per the applicable ASTM, ASME, DIN, or ISO specification for the material grade. TorqBolt provides material test certificates (MTC) per EN 10204 3.1 or 3.2 with every supply.

What sizes are available for Duplex 31803 Socket Cap Screws?

TorqBolt manufactures Duplex 31803 Socket Cap Screws in metric sizes M6 to M100 and imperial sizes 1/4" to 4" diameter, with custom lengths from 10mm to 3000mm. Non-standard sizes are available on request.

Are Duplex 31803 Socket Cap Screws NACE MR0175 / ISO 15156 certified?

Yes, Duplex 31803 Socket Cap Screws can be supplied with NACE MR0175 / ISO 15156-2/3 sour service certification when specified at order. Material certificates and test reports are provided.

What is the typical delivery time for Duplex 31803 Socket Cap Screws?

Standard stock items ship in 1-2 weeks. Custom manufactured Duplex 31803 Socket Cap Screws typically ship in 4-6 weeks depending on quantity, material availability, and certification requirements.

Do you provide third-party inspection for Duplex 31803 Socket Cap Screws?

Yes, third-party inspection by TUV, Lloyd's Register, BV, DNV, SGS, and Intertek is available upon request for Duplex 31803 Socket Cap Screws. Witness testing and stage inspections can be arranged.

Duplex 31803 Socket Cap Screws Supplier

Duplex 31803 Socket Cap Screws Specification

The raw material of these fasteners is classified as Duplex Stainless Steel. Being a PED certified Fasteners Manufacturer by TUV Rheinland,our fasteners are accompanied with EN 10204 3.1/3.2 certification. Duplex 31803 Socket Cap Screws are available in hot forged,cold forged and bar stock machined conditions depending upon the order quantity.

Duplex 31803 Socket Cap Screws Equivalent Designation

UNS Designation	British STD	Werkstoff No.	European STD	Swedish STD	Japanese STD	Forging
S31803	318S13	1.4470	X2CrNiMoN22-5-3	2377	SUS 329J3L	Sa 182 F51

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Duplex 31803 Socket Cap Screws — Specifications & Dimensions

Duplex 31803 Socket Cap screws are externally threaded fasteners typically driven into a tapped hole or self-tapped material. TorqBolt manufactures Duplex 31803 Socket Cap screws per ASME B18.3 (socket products), ASME B18.6.3 (machine screws), DIN 912 / 7991 / 6912, and ISO 4762 / 10642, in metric M3–M48 and imperial 0–1/2".

Drive Types

Hex socket (Allen) — ASME B18.3 / DIN 912, primary for high-torque industrial use

Hex external — wrench-driven, ASME B18.6.3

Phillips, Pozi, Torx (T-series) — assembly-line driver compatibility

Slotted — legacy / specialty applications

Tamper-resistant — pin-Torx, snake-eye, one-way

Head Styles

Duplex 31803 Socket Cap screws are available in cap (cylindrical), button (low-profile dome), countersunk / flat (82° or 90°), pan, fillister, truss, and shoulder configurations. Countersunk per DIN 7991 with 90° head angle is standard for metric; 82° per ASME B18.6.3 for imperial.

Thread & Length

Duplex 31803 Socket Cap screws use full-thread or partial-thread (length-under-head) configurations. Machine screws are typically full-thread; cap screws use partial thread for grip control. Threading per ASME B1.1 (UNC/UNF) or ISO 965 (metric coarse/fine), Class 2A or 6g default. Length-under-head is measured from the bearing surface for hex/cap, from the largest face for countersunk. Custom lengths quoted to drawing.

Specialty Screws

TorqBolt produces Duplex 31803 Socket Cap set screws (cup-point, cone-point, dog-point, flat-point, hex-socket DIN 913/914/915/916), shoulder screws (precision-ground shoulder for pivot applications), and self-tapping screws (Type AB, Type 25). All certified per EN 10204 3.1 / 3.2 with optional NACE MR0175 sour-service compliance.

Duplex & Super Duplex Stainless Steels

Duplex stainless steels have a roughly 50/50 ferrite-austenite microstructure, doubling the yield strength of austenitic 304/316 grades while improving chloride pitting + stress-corrosion resistance. Duplex is the modern default for offshore platform fasteners, desalination plants, and sour-gas piping where austenitics fail to chloride SCC and martensitics fail to hydrogen embrittlement.

Duplex 2205 (UNS S32205 / S31803) is the standard grade with PREN ~35, suitable for chloride-bearing service to ~250°C. Super Duplex 2507 (S32750) and Zeron 100 (S32760) push PREN to 41-42 with higher Cr+Mo+N, qualifying for the most aggressive seawater + sour-well environments. SA-182 F51 / F53 / F55 / F60 are the ASME forged-flange equivalents.

Phase balance is critical: ferrite content must stay within 35-65% in weld + HAZ to maintain corrosion + impact properties (ASTM A923 testing). Solution anneal at 1040-1100°C followed by water quench locks the duplex microstructure. Fasteners ship per ASTM A276 / A479 with EN 10204 3.1 / 3.2 certs including ferrite count and Charpy impact at -46°C. NACE MR0175 / ISO 15156 sour-service certification is standard.

Duplex 31803 Socket Cap Screws