DIN 912 is one of the most common and important standards for socket head cap screws in the world.
In simple terms, DIN 912 is a German industrial standard that specifies the exact dimensions, material, mechanical properties, and technical requirements for a type of socket head cap screw.
Here’s a detailed breakdown of what it means:
Core Characteristics (The “What it looks like”)
· Head: A cylindrical head with a hexagon (6-sided) socket (Allen key drive).· Thread: Can be fully threaded or partially threaded (with an unthreaded shank under the head).· Tip: Usually flat, but can also be specified as chamfered for easier entry.· Key Features: Known for its clean, low-profile head that sits flush or can be counterbored, allowing for high clamping force in a compact space.
Key Specifications (The “Rules”)
The DIN 912 standard precisely defines:
1. Dimensions: Head diameter, head height, socket size, thread pitch, body diameter, and lengths.2. Mechanical Properties: Primarily defined by property class. The most common are: · Class 12.9: The strongest grade (minimum tensile strength of 1220 MPa). Made from alloy steel, heat-treated. Common in high-stress applications. · Class 10.9: High strength (1000 MPa). Also alloy steel, heat-treated. · Class 8.8: Medium strength (800 MPa). · A2-70 / A4-80: Stainless steel grades (A2 = 304, A4 = 316). The number indicates tensile strength (e.g., 700 MPa).3. Materials: Typically carbon steel, alloy steel, or stainless steel.4. Tolerances: How much variation in dimensions is allowed.5. Markings: How the property class must be marked on the head.
Relationship to ISO and Other Standards
· ISO 4762: This is the international equivalent of DIN 912. For decades, DIN 912 was the primary reference. Today, the ISO 4762 standard has largely superseded it globally. The dimensions are essentially identical.· In practice, you will often see bolts labeled as “DIN 912 / ISO 4762.” They are interchangeable. Engineers and buyers use the terms synonymously.· Similar Standards: The closest US analogue is ASME B18.3, but there are small dimensional differences (head height, socket depth). They are not directly interchangeable with DIN 912/ISO 4762 without checking specs.
Common Applications (The “Where it’s used”)
Because of their strength, compact head, and clean look, DIN 912/ISO 4762 socket head cap screws are ubiquitous in precision engineering:
· Machine tools and frames· Automotive and aerospace components· Molds and dies· High-performance bicycles and motorcycles· Robotics and automation equipment· General machinery where a flush or recessed head is needed
Purchasing & Identification
When ordering, you would typically specify:
DIN 912 / ISO 4762 – M8 x 1.25 x 30mm – 12.9
This breaks down as:
· Standard: DIN 912 / ISO 4762· Thread Size: M8 (Metric, 8mm diameter)· Thread Pitch: 1.25mm (standard coarse pitch for M8)· Length: 30mm (measured from under the head to the tip)· Property Class: 12.9 (alloy steel, highest strength)
Summary
DIN 912 is the classic German standard for hex socket head cap screws. While its international successor is ISO 4762, the name “DIN 912” remains the universal industry shorthand for this critical, high-strength fastener found in virtually every piece of modern machinery.
Media Contact
Company Name: Ningbo Zhongli bolts manufacturing Co., Ltd.
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State: Zhejiang
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