ASME B18.2.1-2012 is the latest active version of the standard for inch-series bolts and screws. It specifies dimensions, tolerances, terminology, and quality requirements for a wide range of imperial fasteners used in mechanical engineering, manufacturing, assembly, and industrial projects worldwide.

Compared with the widely used ASME B18.2.1-2010 edition, this 2012 version provides clearer definitions, expanded product coverage, and improved structural standard separation.

What’s New in ASME B18.2.1-2012?

ASME B18.2.1-2012 introduces several key updates and additions compared to the 2010 edition, as confirmed by the official standard’s table of contents:

New Fastener Types Added 

The 2012 edition expands the scope to include three new fastener categories that were not covered in the 2010 version:

• Askew Head Bolts (Table 4)
• Hex Flange Screws (Table 8)
• Lobed Head Screws (Table 9)

These additions provide comprehensive specifications for modern fastening applications not addressed in the previous edition.

Structural Bolts Relocation

Notably, heavy hex structural bolts have been completely removed from ASME B18.2.12012. These fasteners are now specified exclusively under ASME B18.2.6, the dedicated standard for structural applications, eliminating confusion between general-purpose and structural fasteners.

Enhanced Technical Specifications

The standard now includes detailed new sections for critical design parameters:

• Maximum and Minimum Length Limitations for Short Screws Threaded Full Length (Table 11)
• Maximum Grip Gaging Lengths, L_G, and Minimum Body Lengths, L_B, for Screws Except Flange Head (Table 12)

These additions support larger-diameter applications and provide clearer guidance for engineers and manufacturers.

Improved Formatting and Definitions

All tables, notes, and technical definitions have been revised in accordance with ASME B18.12.1, ensuring consistency and readability. Lag screw threads have also been redefined to align with other fastening standards.

Products Covered by ASME B18.2.1-2012

Based on the official table of contents, ASME B18.2.1-2012 covers the following inch-series fasteners:

• Square Head Bolts (Table 1)
• Hex Bolts (Table 2)
• Heavy Hex Bolts (Table 3)
• Askew Head Bolts (Table 4)
• Hex Cap Screws (Table 6)
• Heavy Hex Cap Screws (Table 7)
• Hex Flange Screws (Table 8)
• Lobed Head Screws (Table 9)
• Square Lag Screws (Table 14)
• Hex Lag Screws (Table 15)
• Lag Screw Threads (Table 16)

Important Note: This standard does not cover heavy hex structural bolts, which are now governed by ASME B18.2.6.

Download ASME B18.2.1-2010 & ASME B18.2.1-2012

For reference, you may also review details of the previous widely used edition:

https://www.zzsteels.com/knowledge/asme-b18.2.1-2010.pdf

For the latest specifications, you can access the full document of the active edition:

The post ASME B18.2.1-2012 – The Active Standard appeared first on Supplier of Quality Forged Fittings-Flanges.

ASTM A193 Grade B7 Stud Bolts Specification

ASTM A193 Standard

This specification” covers alloy and stainless steel bolting for pressure vessels, valves, flanges, and fittings for high temperature or high pressure service, or other special purpose applications. See Specification A962/A962M for the definition of bolting. Bars and wire shall be hot-wrought and may be further processed by center less grinding or by cold drawing. Austenitic stainless steel may be carbide solution treated or carbide solution treated and strain-hardened.When strain hardened austenitic steel is ordered, the purchaser should take special care to ensure that Appendix X1 is thoroughly under-stood.

High Temperature Tests

Tests to determine high temperature properties shall be made in accordance with Test Methods E21, E139, and E292, and Practices E150 andE151.

Charpy Impact Tests

Charpy impact tests based on the requirements of specification A320/A320M, shall be made as agreed between the manufacturer and the purchaser. When testing temperatures are as low as those specified in specification A320/A320M, bolting should be ordered to that specification in preference to this specification

100 % Hardness Testing of Grade B7M

Each Grade B7M bolt or stud shall be tested for hardness by indentation method and shall meet the requirements specified in tables

 Length Tolerances for Bolts

ASTM A193 Grade B7 Stud Bolts Material

ASTM A193 Grade B7 Chemical Composition

Manganese is usually between 0.65 and 1.10%. Manganese helps to improve the strength, hardness and toughness of steel, and can improve the deoxidation and desulfurization effects of steel, enhancing the overall performance of steel.

ASTM A193 B7 Mechanical Property

The minimum elongation of ASTM A193 Grade B7 stud bolts is 16%. A certain elongation indicates that the bolt has a certain plastic deformation capacity, which is very important when subjected to dynamic loads or uneven loads. It can adapt to stress changes through plastic deformation and prevent the bolt from breaking suddenly.

ASTM A193 Grade B7 Recommended Hardware

Difference Between A193 Grade B7 & A193 Grade B7M Stud bolts

Hardness is probably the most important difference between A193 B7M & A193 B7. The maximum hardness of ASTM A193 B7M is 235 HB or 99 HRB, while the maximum hardness of ASTM A193 Grade B7 stud bolts are 321 HB or 35 HRC. The most notable difference from a manufacturing perspective is that when supplying A193 B7M bolts, each individual bolt or stud in the batch must be tested for hardness. A193 B7M fasteners also require a different type of heavy-duty hex nut than A193 B7, namely ASTM A194 Grade 2HM.

While A193 B7 is specified relatively often in the construction industry, A193 B7M is a specification not seen as regularly. This makes it important to understand the differences between the two specifications so that the right material is ultimately supplied.

The post ASTM A193 Grade B7 Stud Bolts appeared first on Supplier of Quality Forged Fittings-Flanges.