ASTM A193 Fasteners

 

ASTM A193 Fasteners Manufacturers | ASTM Fasteners Stockists

 

ASTM 193/A 193M is the standard that covers alloy and stainless steel bolting material for pressure vessels, valves, flanges, and fittings for high-temperature service. The term bolting material as used in this specification covers bars, bolts, screws, studs, stud bolts, and wire. Bars and wire shall be hot-wrought. The material 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.  One of the most common alloy and stainless industrial fasteners is the Grade B7 studs and Grade B8 stud respectively.

 

Several grades are covered, including ferritic steels and austenitic stainless steels designated B5, B8, and so forth. Selection will depend upon design, service conditions, mechanical properties, and high-temperature characteristics.

 

Unifit Metalloys Inc is one of the well known Manufacturers of ASTM A193 Fasteners in India. Unifit Metalloys Inc Manufactures this product from Best quality Raw Materials. Raw Material procured is being inspected by the Quality control department and then processed further for Manufacturing. The Fasteners Manufactured are of the best quality and prime finished. Unifit Metalloys Inc maintains Large Ready Stock of Different Size of Fasteners to over come the shortage of Lead Delivery Time. UMI Believes in Timely Delivery and Best price for its customers.
 

Bolting Grades

 

Grade Tensile Class Raw Material Description
B5   4-6% Chromium Ferritic Steel
B6   13% Chromium Ferritic Steel
B6X   13% Chromium Ferritic Steel
B7   Chromium Molybdenum Alloy Steel, Quenched & Tempered
B7M   Chromium Molybdenum Alloy Steel, Quenched & Tempered
B16   Chromium-molybdenum-vanadium Alloy Steel, Quenched & Tempered
B8 Class 1 AISI 304 Stainless Steel, Carbide Solution Treated
B8 Class 2 AISI 304 Stainless Steel, Carbide Solution Treated and Strain Hardened
B8A   AISI 304 Stainless Steel, Carbide solution treated in the finished condition
B8C Class 1 AISI 347 Stainless Steel, Carbide Solution Treated
B8C Class 2 AISI 347 Stainless Steel, Carbide Solution Treated and Strained Hardened
B8CA   AISI 347 Stainless Steel, Carbide Solution Treated in Finished Condition
B8M Class 1 AISI 316 Stainless Steel, Carbide Solution Treated
B8M Class 2 AISI 316 Stainless Steel, Carbide Solution Treated and Strain Hardened
B8MA   AISI 316 Stainless Steel, Carbide Solution Treated in Finished Condition
B8M2   AISI 316 Stainless Steel, Carbide Solution Treated and Strain Hardened
B8M3   AISI 316 Stainless Steel, Carbide Solution Treated and Strain Hardened
B8P Class 1 AISI 305 Stainless Steel, Carbide Solution Treated
B8P Class 2 AISI 305 Stainless Steel, Carbide Solution Treated and Strain Hardened
B8PA   AISI 305 Stainless Steel, Carbide Solution Treated in Finished Condition
B8N   AISI 304N Stainless Steel, Carbide Solution Treated
B8N   AISI 304N Stainless Steel, Carbide Solution Treated and Strain Hardened
B8MLCuN   AISI 304N Stainless Steel, Carbide Solution Treated and Strain Hardened
B8MLCuN   UNS S31254 Stainless Steel, Carbide Solution Treated and Strain Hardened
B8MLCuNA   UNS S31254 Stainless Steel, Carbide Solution Treated
B8T Class 1 AISI 321 Stainless Steel, Carbide Solution Treated
B8T Class 2 AISI 321 Stainless Steel, Carbide Solution Treated and Strain Hardened
B8TA   AISI 321 Stainless Steel, Carbide Solution Treated in Finished Condition
B8R   Nitronic 50/UNS S20910 Stainless Steel, Carbide Solution Treated
B8RA   Nitronic 50/UNS S20910 Stainless Steel, Carbide Solution Treated in Finished Condition
B8S   Nitronic 60/UNS S21800 Stainless Steel, Carbide Solution Treated
B8SA   Nitronic 60/UNS S21800 Stainless Steel, Carbide Solution Treated
B8LN   AISI 304LN Stainless Steel, Carbide Solution Treated
B8LNA   AISI 304LN Stainless Steel, Carbide Solution Treated in Finished Condition
B8MLN   AISI 316LN Stainless Steel, Carbide Solution Treated
B8MLNA   AISI 316LN Stainless Steel, Carbide Solution Treated in Finished Condition
B8CLN   AISI 347LN Stainless Steel, Carbide Solution Treated
B8CLNA   AISI 347LN Stainless Steel, Carbide Solution Treated in Finished Condition
 
 

ASTM A193 Chemical Composition

 

Each alloy shall conform to the chemical composition requirements.

 

Ferritic Steels
Element Grade B5 Grade B6, B6X Grade B7, 7M Grade B16
Carbon 0.10 min 0.08-0.15 0.37-0.49 0.36-0.47
Manganese, max 1.00 1.00 0.65-1.10 0.45-0.70
Phosphorus, max 0.040 0.040 0.035 0.035
Sulfur, max 0.030 0.030 0.040 0.040
Silicon 1.00 max 1.00 max 0.15-0.35 0.15-0.35
Chromium 4.00-6.00 11.5-13.5 0.75-1.20 0.80-1.15
Molybdenum 0.40-0.65 0.15-0.25 0.50-0.65
Vanadium 0.25-0.35
Aluminium, max 0.015
 
 
Austenitic Steels, Classes 1, 1A, 1D, and 2
Element Grade B8, B8A Grade B8C, B8CA Grade B8M, B8MA, B8M2, B8M3
Carbon, max 0.08 0.08 0.08
Manganese, max 2.00 2.00 2.00
Phosphorus, max 0.045 0.045 0.045
Sulfur, max 0.030 0.030 0.030
Silicon, max 1.00 1.00 1.00
Chromium 18.0-20.0 17.0-19.0 16.0-18.0
Molybdenum 2.00-3.00
Columnium + Tantalum 10 x carbon content, min – 1.10 max
 
 
Austenitic Steels, Classes 1A, 1B, 1D, and 2
Element Grade B8N, B8NA Grade B8MN, B8MNA Grade B8MLCuN, B8MLCuNA
Carbon 0.10 min 0.08-0.15  
Manganese, max 1.00 1.00  
Phosphorus, max 0.040 0.040  
Sulfur, max 0.030 0.030  
Silicon 1.00 max 1.00 max  
Chromium 4.00-6.00 11.5-13.5  
Molybdenum 0.40-0.65  
Columnium + Tantalum    
 
 
Austenitic Steel, Classes 1, 1A and 2
Element Grade B8T, B8TA
Carbon 0.10 min
Manganese, max 1.00
Phosphorus, max 0.040
Sulfur, max 0.030
Silicon 1.00 max
Chromium 4.00-6.00
Molybdenum 0.40-0.65
 
 
Austenitic Steels, Classes 1C and 1D
Element Grade B8R, B8RA Grade B8S, B8SA
Carbon, max 0.10 min 0.08-0.15
Manganese 4.00-6.00 1.00
Phosphorus, max 0.040 0.040
Sulfur, max 0.030 0.030
Silicon 1.00 max 1.00 max
Chromium 4.00-6.00 11.5-13.5
Molybdenum 0.40-0.65
 
 

ASTM A193 Mechanical Properties

 

The material as represented by the tension specimens shall conform to the requirements at room temperature after heat treatment. Alternatively, stainless strain hardened fasteners (Class 2, 2B, and 2C) shall be tested full size after strain hardening to determine tensile strength and yield strength and shall conform to the requirements prescribed in Table 2 and 3. Should the results of full size tests conflict with results of tension specimen tests, full size test results shall prevail.

 

Grade Diameter Tensile Strength Yield Strength Elongation Reduction Hardness
Grade B5 Up to M100, inclusive 690 550 16 50
Grade B6 Up to M100, inclusive 760 585 15 50
Grade B6X Up to M100, inclusive 620 485 16 50 26 HRC
Grade B7 M64 and under 860 720 16 50 321 HBW or 35 HRC
Grade B7 Over M64 to M100 795 655 16 50 321 HBW or 35 HRC
Grade B7 Over M100 to M180 690 515 18 50 321 HBW or 35 HRC
Grade B7M M100 and under 690 550 18 50 235 HBW or 99 HRB
Grade B7M M100 and over 690 515 18 50 235 HBW or 99 HRB
Grade B16 M64 and under 860 725 18 50 321 HBW or 35 HRC
Grade B16 Over M64 to M100 760 655 17 45 321 HBW or 35 HRC
Grade B16 Over M100 to M180 690 585 16 45 321 HBW or 35 HRC
Grade B8, B8M, Class 1, 1D All Diameters 515 205 30 50 223 HBW or 96 HRB
Grade B8, B8C, B8T, Class 2 M20 and under 860 690 12 35 321 HBW or 35 HRC
Grade B8, B8C, B8T, Class 2 M20 to M24, inclusive 690 550 20 45 321 HBW or 35 HRC
Grade B8, B8C, B8T, Class 2 M24 to M30, inclusive 655 450 25 45 321 HBW or 35 HRC
Grade B8, B8C, B8T, Class 2 M30 to M36, inclusive 620 345 30 45 321 HBW or 35 HRC
Grade B8, B8M2, Class 2B M48 and under 655 515 25 40 321 HBW or 35 HRC
Grade B8, B8M2, Class 2B M48 to M64, inclusive 620 450 30 40 321 HBW or 35 HRC
Grade B8, B8M2, Class 2B M64 to M72, inclusive 550 380 30 40 321 HBW or 35 HRC
Grade B8A, B8MA, B8CA, B8TA, B8MLCuNA, Class 1A All Diameters 515 205 30 50 192 HBW or 90 HRB
Grade B8M, B8MLCuN, Class 2 M20 and under 760 655 15 45 321 HBW or 35 HRC
Grade B8M, B8MLCuN, Class 2 M20 to M24, inclusive 690 550 20 45 321 HBW or 35 HRC
Grade B8M, B8MLCuN, Class 2 M24 to M30, inclusive 655 450 25 45 321 HBW or 35 HRC
Grade B8M, B8MLCuN, Class 2 M30 to M36, inclusive 620 345 30 45 321 HBW or 35 HRC
Grade B8M3, Class 2C M48 and under 585 450 30 60 321 HBW or 35 HRC
Grade B8M3, Class 2C Over M48 585 415 30 60 321 HBW or 35 HRC
Grade B8C, B8T, Class 1 All Diameters 515 205 30 50 192 HVW or 90 HRB
Grade B8R, Class 1C, 1D All Diameters 690 380 35 55 271 HBW or 28 HRC
Grade B8RA Class 1C All Diameters 690 380 35 55 271 HBW or 28 HRC
Grade B8S, Class 1C, 1D All Diameters 655 345 35 55 271 HBW or 28 HRC
Grade B8SA Class 1C All Diameters 655 345 35 55 271 HBW or 28 HRC
 
 

Heat Treatment

 

Ferritic steels shall be allowed to cool to a temperature below the cooling transformation range immediately after rolling or forging. Materials shall then be uniformly reheated to the proper temperature to refine the grain (a group thus reheated being known as a quenching charge), quenched in a liquid medium under substantially uniform conditions for each quenching charge, and tempered. The minimum tempering temperature shall be as specified in Tables 2 and 3.

 

Recommended Nuts & Washers

 
Bolting Grade Nut Grade Washer Grade
ASTM A193 Grade B6, B6X ASTM A194 Grade 6 Mild Steel
ASTM A193 Grade B7,7M ASTM A194 Grade 2H, 2HM ASTM F436
ASTM A193 Grade B16 ASTM A194 Grade 16 ASTM F436
ASTM A193 Grade B8 ASTM A194 Grade 8 SS 304
ASTM A193 Grade B8M, B8MA, B8M2, B8M3 ASTM A194 Grade 8M, 8MA SS 316
ASTM A193 Grade B8C, B8CA ASTM A194 Grade 8C, 8CA SS 347
ASTM A193 Grade B8T, B8TA ASTM A194 Grade 8T, 8TA SS 321
ASTM A193 Grade B8MLCuN, B8MLCuNA ASTM A194 Grade 8MLCuN, 8MLCuNA 254SMO / UNS S31254
ASTM A193 Grade B8R, B8RA ASTM A194 Grade 8R, 8RA Nitronic 50/UNS S20910
ASTM A193 Grade B8S, B8SA ASTM A194 Grade 8S, 8SA Nitronic 60/UNS S21800