STS Industrial - Bolts & Screws

 

ASTM A193 GRADE B7 MODIFIED STUD BOLTS

GOVERNING STANDARDS:
ASTM A193/A193M Standard specification for alloy-steel and stainless steel bolting for high temperature or high pressure service and other special purpose applications.
ASME B16.5 Covers recommended stud bolt quantity, diameter, and length for use in flanged pipe fittings.
ASME B1.1 Class 2A Specifies the thread form, series, class, allowance, tolerance, and desig nation for unified screw threads. UNC for 1″ diameter and smaller. UN8 (8 threads per inch) for 1-1/8″ diameter and larger.

 

APPLICATIONS:

Typically used in sour gas service where Hydrogen Sulfide gas exposure may lead to Hydrogen embrittlement problems.  For B7M fasteners, the final heat treating process must be done after all machining and forming operations, including thread rolling and any type of cutting.

ASTM A193 Grade B7 Stud Bolt Marking

Product to be marked with the manufacturer’s marking and grade marking on one end of each stud 3/8″ diameter and larger. Manufacturer’s marking may be placed on other end if insufficient space. 

  • COMPATIBLE NUTS

    ASTM A194 Grade 2HM Heavy Hex

MATERIAL PROPERTIES:
Chromium- Molybdenum Alloy Steel, AISI 4140, 4142, 4145, 4140H, 4142H or 4145H Quenched and Tempered

DIAMETER

PROOF LOAD

YIELD STRENGTH

TENSILE STRENGTH

CORE HARDNESS

up through 4″

80,000 psi 100,000 psi

B99 Max

4-1/8″ through 7″

75,000 psi 100,000 psi

B99 Max

Elongation 18% Minimum (All Diameters)
Reduction of Area 50% Minimum (All Diameters)
Material strengths listed are minimum acceptable per governing standard. Core hardness based on Rockwell scale.

 

STUD REFERENCE CHART:

The chart below gives the recommended stud bolt diameter, length, and quantity for a given flange size.

FLANGE NOMINAL PIPE DIAMETER (in.)
RATING BOLTING 1/2 3/4 1 1-1/4 1-1/2 2 2-1/2 3 3-1/2 4
150# Number 4 4 4 4 4 4 4 4 8 8
Diameter 1/2 1/2 1/2 1/2 1/2 5/8 5/8 5/8 5/8 5/8
Stud Bolt Length 2-1/4 2-1/2 2-1/2 2-3/4 2-3/4 3-1/4 3-1/2 3-1/2 3-1/2 3-1/2
Mach Bolt Length 2 2 2-1/4 2-1/4 2-1/2 2-3/4 3 3 3 3
300# Number 4 4 4 4 4 8 8 8 8 8
Diameter  1/2  5/8  5/8  5/8  3/4  5/8  3/4  3/4  3/4  3/4
Stud Bolt Length 2-1/2 3 3 3-1/4 3-1/2 3-1/2 4 4-1/4 4-1/4 4-1/2
Mach Bolt Length 2-1/4 2-1/2 2-1/2 2-3/4 3 3 3-1/4 3-1/2 3-3/4 3-3/4
600# Number 4 4 4 4 4 8 8 8 8 8
Diameter  1/2  5/8  5/8  5/8  3/4  5/8  3/4  3/4  7/8  7/8
Stud Bolt Length 3 3-1/2 3-1/2 3-3/4 4-1/4 4-1/4 4-3/4 5 5-1/2 5-3/4
900# Number 4 4 4 4 4 8 8 8 8
Diameter  3/4  3/4  7/8  7/8 1  7/8 1 7/8 1-1/8
Stud Bolt Length 4-1/4 4-1/2 5 5 5-1/2 5-3/4 6-1/4 5-3/4 6-3/4
1500# Number 4 4 4 4 4 8 8 8 8
Diameter  3/4  3/4  7/8  7/8 1  7/8 1 1-1/8 1-1/4
Stud Bolt Length 4-1/4 4-1/2 5 5 5-1/2 5-3/4 6-1/4 7 7-3/4
2500# Number 4 4 4 4 4 8 8 8 8
Diameter  3/4  3/4  7/8 1 1-1/8 1 1-1/8 1-1/4 1-1/2
Stud Bolt Length 4-3/4 5 5-1/2 6 6-3/4 7 7-3/4 8-3/4 10
FLANGE NOMINAL PIPE DIAMETER (in.)
RATING BOLTING 5 6 8 10 12 14 16 18 20 24
150# Number 8 8 8 12 12 12 16 16 20 20
Diameter 3/4 3/4 3/4 7/8 7/8 1 1 1-1/8 1-1/8 1-1/4
Stud Bolt Length 3-3/4 4 4-1/4 4-1/2 4-3/4 5-1/4 5-1/4 5-3/4 6-1/4 6-3/4
Mach Bolt Length 3-1/4 3-1/4 3-1/2 4 4 4-1/2 4-1/2 5 5-1/2 6
300# Number 8 12 12 16 16 20 20 24 24 24
Diameter  3/4  3/4  7/8 1 1-1/8 1-1/8 1-1/4 1-1/4 1-1/4 1-1/2
Stud Bolt Length 4-3/4 4-3/4 5-1/2 6-1/4 6-3/4 7 7-1/2 7-3/4 8 9
Mach Bolt Length 4-1/4 4-1/4 4-3/4 5-1/2 5-3/4 6-1/4 6-1/2 6-3/4 7-1/4 8
600# Number 8 12 12 16 20 20 20 20 24 24
Diameter 1 1 1-1/8 1-1/4 1-1/4 1-3/8 1-1/2 1-5/8 1-5/8 1-7/8
Stud Bolt Length 6-1/2 6-3/4 7-1/2 8-1/2 8-3/4 9-1/4 10 10-3/4 11-1/4 13
900# Number 8 12 12 16 20 20 20 20 20 20
Diameter 1-1/4 1-1/8 1-3/8 1-3/8 1-3/8 1-1/2 1-5/8 1-7/8 2 2-1/2
Stud Bolt Length 7-1/2 7-1/2 8-3/4 9-1/4 10 10-3/4 11-1/4 12-3/4 13-3/4 17-1/4
1500# Number 8 12 12 12 16 16 16 16 16 16
Diameter 1-1/2 1-3/8 1-5/8 1-7/8 2 2-1/4 2-1/2 2-3/4 3 3-1/2
Stud Bolt Length 9-3/4 10-1/4 11-1/2 13-1/4 14-3/4 16 17-1/2 19-1/2 21-1/4 24-1/4
2500# Number 8 8 12 12 12
Diameter 1-3/4 2 2 2-1/2 2-3/4
Stud Bolt Length 11-3/4 13-1/2 15 19-1/4 21-1/4

 

 

All dimensions in inches unless otherwise noted.

Sources: ASTM Standards for Mechanical Fasteners and Related Processes 2nd Edition, Inch Fastener Standards 8th Edition

Note: All material included on this page is informational only, and should not be used as one’s sole source for design purposes. STS Industrial, Inc. and its affiliates do not guarantee the accuracy of the information on this site, and retain no liability for the use or misuse of the information contained on this site.