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Screws › Countersunk & Flat-Head Machine Screws

Alloy Steel Black Oxide DIN7991 Socket Flat Screw

Updated 2026-11-04 · Markdown version

Model no. DIN7991

US$0.261,000–4,999 pieces

US$0.135,000+ pieces

MOQ 1,000 pieces · Final price confirmed in your quote

Material: High Strength Steel
Head Style: Hexagonal
Standard: DIN, GB, ANSI, BSW, JIS, GOST
Grade: 10.9
Surface Treatment: Black Oxide/Plain
Head Shape: Flat Head Cap
Raw Material: Alloy Steel / Stainless Steel

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Specifications are as listed for this product. Engineering Hardware & Fasteners confirms ratings, mating parts, compatibility, packing and lead time with you before you order.

Specifications

Customization	Available
Material	High Strength Steel
Type	Countersunk Head
Groove	Hexagon
Connection	Common Bolt
Head Style	Hexagonal
Standard	DIN, GB, ANSI, BSW, JIS, GOST
Grade	10.9
Surface Treatment	Black Oxide/Plain
Head Shape	Flat Head Cap
Raw Material	Alloy Steel / Stainless Steel
MOQ	One Master Carton(Around 25-30kgs) for Each Size
Application	Machinery
Model No.	DIN7991
Transport Package	1. Small Boxes Outer Carton 2. Bulk Packaging
Specification	M3-M20
Origin	China
HS Code	731815
Production Capacity	1000 Tons Per Month
include	Drop-in Anchor
Production Range	Diameter
Package	25-30KGS/CARTON,36-48CARTONS/PALLET
Produce time	Standard sizes in stock 15-30 working days, Non-standard sizes,
by Air, Express,like Fedex, UPS, DHL,etc. More than 100KGS	By sea, we have
Bulk order	15-30 working days(Standard).
Category	Countersunk & Flat-Head Machine Screws

Technical parameters

Material	1.Stainless Steel:SS304,SS316 2.Alloy Steel
Grade	8.8, 10.9, 12.9
Finish	Plain(Black oxide), Zinc Plated(White/Yellow), H.D.G and etc.
Thread	Metric,UNC,UNF,BSW
Standard	ISO, DIN, ASME, JIS, BS and Non-standard
Sample Service	Samples can be in free when you confirm our price is acceptable.
Certificate	ISO9001,CE, SGS
Advantage	1. Competitive price; 2. OEM service available
Packing	1. Bulk in cartons (25-30kg Max.)+wooden pallet 2. Small Boxes into outer carton + wooden pallet 3. According to customer special demand
Payment terms	FOB, CIF, CFR, L/C, or others.
Delivery method	by sea, by air or by express service
Lead Time	15-30 work days after order confirmed
Application	Structural Steel; Metal Buliding; Oil&Gas; Tower&Pole; Wind Energy; Mechanical Machine; Automobile; Home Decorating and etc.
Notes	Special specifications and marks can be made according to customers requirements;

Description

Alloy Steel Black Oxide DIN7991 Socket Flat Screw is part of our countersunk & flat-head machine screws range (Screws).

Key details

Type: Countersunk Head
Standard: DIN, GB, ANSI, BSW, JIS, GOST
Material: High Strength Steel
Grade: 10.9
Head Style: Hexagonal
Groove: Hexagon
Surface Treatment: Black Oxide/Plain
Connection: Common Bolt

Available configurations include material, head style, standard, grade and surface treatment. Custom sizes, threads, materials, grades, platings and packaging can be quoted on request.

Ordering through Engineering Hardware & Fasteners

Minimum order is 1,000 pieces at US$0.13 – 0.26 per piece. Send one inquiry with the part number, quantity and destination, and Engineering Hardware & Fasteners confirms size, thread, material, grade, finish, price, lead time and shipping, checks the goods before dispatch and ships them to you.

Frequently asked questions

What is the minimum order quantity (MOQ) for Alloy Steel Black Oxide DIN7991 Socket Flat Screw?

The listed minimum order is 1,000 pieces, at US$0.13 – 0.26 per piece. Smaller trial quantities or samples can be requested in your inquiry; Engineering Hardware & Fasteners confirms what is possible for your size.

How does the price change with quantity?

Volume pricing: US$0.26 for 1,000–4,999 pieces; US$0.13 for 5,000+ pieces. Final prices depend on size, material, finish and packing and are confirmed in your quote.

What are the main specifications of Alloy Steel Black Oxide DIN7991 Socket Flat Screw?

Type: Countersunk Head; Standard: DIN, GB, ANSI, BSW, JIS, GOST; Material: High Strength Steel; Grade: 10.9; Head Style: Hexagonal; Groove: Hexagon. The full specification table and any technical parameter tables are listed on this page.

Can this product be customized (OEM)?

Listed configurations include material, head style, standard, grade and surface treatment. Size, thread, length, material and grade, surface finish, head marking, packaging and labels can be quoted to your specification or drawing.

What is the lead time and how is it shipped?

Lead time depends on quantity and customization and is confirmed in your quote. Engineering Hardware & Fasteners checks the goods before dispatch and ships by express, air or sea; mixed orders can be consolidated in one shipment.

Which other countersunk & flat-head machine screws are available?

The Countersunk & Flat-Head Machine Screws category lists 2,424 products in different sizes, materials and finishes: https://engineeringhardware.com/fastener-products/screws/countersunk-flat-head-machine-screws/

How we work

Specified, checked and shipped by Engineering Hardware & Fasteners

Engineering Hardware & Fasteners supplies bolts, screws, nuts, washers, anchors, rivets and fastening hardware to equipment makers, contractors, distributors and maintenance teams. Orders go through one controlled process: size, thread, material, grade and finish confirmed, samples approved, dimensions, thread fit and plating checked before packing, then packed for export — standard or made to drawing.

DIN, ISO, ASTM, ANSI, JIS and GB standard parts
Non-standard parts made to your drawing
Dimensions, thread gauges and plating checked before packing
Export cartons and pallets, consolidated mixed orders
Samples available for approval before mass production

More about us → · Request a sample or custom quote →

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US$0.13 – 0.26MOQ 1,000 piecesGet a quote WA