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ASTM A193 B8 Bolts

ASME SA 193 Grade B8 Stud and Hex Bolt Manufacturer in India

ASTM A193 B8 Bolts

Great Steel & Metals is a manufacturer and supplier of stainless steel bolts, nuts and other fasteners. We offer the best products out of different material.

The ASTM A193 Grade B8 Bolts are used in high temperature and high corrosion environments such as chemical processing plants and in power generation plants. The ASTM A193 B8 Class 2 Bolts are used in heat exchangers as well. They could be used in high corrosive environments such as marine industries, dyeing industries and mining industries. The ASTM A193 B8 Nuts are stronger and harder and do not wear off quickly. The grade B8 has two classes. class 2 is stronger than class 1. The class 2 has higher HBW at 321 max and lower HRC at 35 max. These properties allow these two classes to be used uniquely with unique applications. The ASTM A193 B8 Studs can be used along with ASTM A193 B8 Threaded Rod in high heat applications because they are heated and water quenched to provide maximum corrosion resistance and strength. Our B8 Hex Nut is used with tight connections where strength is more important. All our products are of high quality and we test them prior to shipping. You can submit your inquiries and we will be in contact with all the details you want.

ASTM A193 B8 Bolts

ASTM A193 B8 Bolts

ASME SA 193 Grade B8 Stud

ASME SA 193 Grade B8 Stud

ASTM A193 B8 Threaded Rod

ASTM A193 B8 Threaded Rod


Buy ASTM A193 Grade B8 Threaded Rod and Heavy Hex Bolt as Per Required Specification

Specification Schedule of ASME SA 193 Grade B8 Stud

ASTM A193 B8 hex bolt sizes

ASTM A193 B8 hex bolt sizes

  • Imperial :  1/4" to 4"
  • Metric : M1.2 – M48
ASTM A193 Grade B8 Double End Stud Sizes

ASTM A193 Grade B8 Double End Stud Sizes

  • M6 to M152
  • 1/4" to 8"
SA193 B8 hex cap screw size

SA193 B8 hex cap screw size

  • M6 to M152
  • 1/4" to 8"
ASTM A193 gr B8 Anchor Bolts Sizes

ASTM A193 gr B8 Anchor Bolts Sizes

  • #10 to 1"
  • M8 – M72
A193 B8 Stainless Steel Eye Bolt

A193 B8 Stainless Steel Eye Bolt

  • 1/2" to 8"
  • M8 – M100
ASME SA193 Grade B8 U Bolts Sizes

ASME SA193 Grade B8 U Bolts Sizes

  • 1/2" to 24"
  • DN 20 to DN500
ASME SA193 B8  bolt head types

ASME SA193 B8 bolt head types

  • Combination Drive
  • Truss
  • Hex head
  • Flat
  • Hex washer head
  • Slotted hex washer
  • Socket cap head
  • Slotted Drive
  • Pan
  • Button head
  • Phillips Drive
  • Frearson Drive
  • Oval
  • Hex / Socket / Allen Drive
SA 193 Gr B8 shoulder bolt thread standards

SA 193 Gr B8 shoulder bolt thread standards

  • ISO 68-1
  • ISO 724
  • ISO 268
  • BS 84
  • ASME B1.1
  • BS 3643
  • ASME B1.13M
Heavy hex structural bolts manufacturing techniques

Heavy hex structural bolts manufacturing techniques

  • Cold Forged
  • CNC machined
  • Hot Forged
A193 B8 SS  bolts head drive

A193 B8 SS bolts head drive

  • Slotted
  • Phillips/Slot
  • Phillips
  • Six-Lobe
ASTM Standard

A193 gr b8 material ASTM Standard

  • ASTM A193
  • ASME SA193
A193 stainless steel bolts class

A193 stainless steel bolts class

  • Class 1
  • Class 2
ASTM A193 Grade B8 Stainless Steel Machine Bolt End

ASTM A193 Grade B8 Stainless Steel Machine Bolt End

  • Semi-cone point
  • Cone point
  • Gimlet point
  • Sheared end
  • Chisel point
  • Milled end
  • 45 degree angle cut
  • Half point
  • Chamfer end
ASTM A193 gr 8 socket head cap screws surface coating

ASTM A193 gr 8 socket head cap screws surface coating

  • Mechanical
  • Plain
  • Green Finish
  • Oil
  • Clear Zinc Plated
  • PTFE / Teflon
  • Nickel Plated
  • Zinc Nickel
  • Black Finish
  • Hot Dip Galvanized
  • Yellow Zinc Plated
  • Cadmium
  • Black Oxide
SA193 B8 Class 1 shoulder bolt tensile strength

SA193 B8 Class 1 shoulder bolt tensile strength

  • 125 ksi
ASME SA193 B8 Class 1 socket head yield strength

ASME SA193 B8 Class 1 socket head yield strength

  • 105 ksi
ASTM A193 Grade b8 Class 2 Bolt Marking

ASTM A193 Grade b8 Class 2 Bolt Marking 

  • Schedule
  • Grade
  • Heat Number
  • Size
  • Manufacturer’s Name or Logo
  • Specification
  • Method of Manufacturing
Services

Services

  • Mil-Spec Packaging
  • Bagging
  • JIT
  • Head Painting
  • Plating
  • Venting
  • Head Shank Drilling
  • Thread Locking
Density

Density

  • 8000 Kg/m3
Electrical Resistivity

Electrical Resistivity

  • 77 nΩ.m
Origin

Origin

  • American
  • Korean
  • Janpanese
  • European
  • Russia
ASTM A193 gr 8 threaded rod  packaging methods

ASTM A193 gr 8 threaded rod packaging methods

  • Custom
  • Crates
  • Wooden Boxes
  • Wrapped in plastic
Elastic Modulus

Elastic Modulus

  • 193 Gpa
Elongation

Elongation

  • 30 %
Certification

Certification 

  • Lab. Test Report from Govt. Approved Lab
  • DFARS compliant
  • Heat Treatment Charts
  • Third Party Inspection Report
  • MTC EN 10204 3.1/3.2
  • HS Code
  • Raw Materials Certificate
  • Commercial Invoice
  • Moisture testing report
  • Fumigation Certificates
  • Form A for GSP
  • Surface roughness measurement
B8 Grade Stainless Steel Fasteners Testing Methods

B8 Grade Stainless Steel Fasteners Testing Methods

  • Wedge Testing
  • UT
  • Hardness
  • Image Dimension Measuring
  • Micro Etch
  • DPI
  • Stress Rupture
  • Chemical Analysis
  • Intergranular Corrosion
  • Elevated Tensile
  • Proof Load
  • Charpy
  • Tensile
  • MPI
  • PMI
A193 B8 Set Screws Point

A193 B8 Set Screws Point 

  • Half dog
  • Cup
  • Cone
  • Knurled cup
  • Full dog
  • Flat
SA 193 B8 CSK  screws drill point

SA 193 B8 CSK screws drill point

  • Type AB Milled Point
  • Type B
  • Type A
  • Type AB
  • Type 17 A-milled point
Types of ASME SA193 Gr B8 threaded rod

Types of ASME SA193 Gr B8 threaded rod

  • ASTM B8 fully threaded rod
  • ASTM A193 Grade B8 right and left hand threaded rod
  • ASTM A 193 GR B8 tap end threaded rod
  • SA 193 Gr B8 extra fine threaded rod
  • SA193 B8 double ended threaded rod
A193 Grade B8 Eye Bolts DIN Standards

A193 Grade B8 Eye Bolts DIN Standards

  • DIN 967
  • DIN 931
  • DIN 6914
  • DIN 933
  • DIN 912
  • DIN 916
  • DIN 7991
SA 193 Grade B8 bolts thread types

SA 193 Grade B8 bolts thread types

  • Fine Thread
  • Trapezoidal
  • UNJ
  • UNEF
  • 12-thread series
  • Metric fine
  • BSF
  • Metric coarse
  • 8-Thread Series
  • ACME
  • Coarse thread
SA 193 Gr B8 stud bolt types

SA 193 Gr B8 stud bolt types

  • ASTM A193 B8 reduced shank stud bolts
  • A193 gr 8 hub studs
  • A193 B8 double end stud bolts
  • SA 193 B8 UNC stud bolt
  • A193 Gr B8 blade studs
  • ASTM B8 tap end stud bolts
  • ASTM A193 Grade B8 welding studs
  • ASTM A 193 GR B8 exhaust stud bolt
  • SA 193 Gr B8 fully threaded studs
  • SA193 B8 knurled stud bolt
  • B8 Stainless Steel continuous threaded stud bolts
A193 Gr B8 screw types

A193 Gr B8 screw types

  • ASTM A193 B8 self drilling screws
  • A193 gr 8 fully threaded screws
  • A193 B8 hex cap screws
  • SA 193 B8 socket cap screws
  • A193 Gr B8 coach screws
  • ASTM B8 masonry screws
  • ASTM A193 Grade B8 hex lag screws
  • ASTM A 193 GR B8 self drilling screws
  • SA 193 Gr B8 countersunk slotted screws
  • SA193 B8 socket screws
  • B8 Stainless Steel socket head cap screw
  • A193 GRB8 panel screws
  • ASTM A193 gr B8 allen cap screws
  • ASTM A193 gr 8 set screws
  • A193 B8 SS 304 cap screw
  • B8 Grade Stainless Steel anchor screws
  • A193 B8 Stainless Steel self tapping screws
  • ASTM A193 Grade B8 Stainless Steel thread cutting machine screws
  • Grade B8 Stainless Steel concrete screws
  • ASTM A193 B8 Stainless Steel machine screws
  • SA 193 Grade B8 grub screws
  • ASME SA193 Grade B8 sheet metal screws
  • ASME SA193 Gr B8 hexagon screw
  • A193 Grade B8 wood screws
  • ASME SA193 B8 sammys screws
  • ASTM A193 B8 flange 12-point screws
  • A193 gr 8 deck screws
Types of ASTM A193 gr 8 bolt

Types of ASTM A193 gr 8 bolt

  • ASTM A193 B8 stove bolt
  • A193 gr 8 hanger bolt
  • A193 B8 hex bolts
  • SA 193 B8 plow bolt
  • A193 Gr B8 step bolt
  • ASTM B8 hex head bolt
  • ASTM A193 Grade B8 carriage bolt
  • ASTM A 193 GR B8 eye bolts
  • SA 193 Gr B8 round head bolts
  • SA193 B8 heavy hex bolt
  • B8 Stainless Steel t-head bolt
  • A193 GRB8 socket bolt
  • ASTM A193 gr B8 tap bolt
  • ASTM A193 gr 8 square bolts
  • A193 B8 SS 304 draw bolt
  • B8 Grade Stainless Steel machine bolt
  • A193 B8 Stainless Steel shoulder bolt
  • ASTM A193 Grade B8 Stainless Steel t-head bolt
  • Grade B8 Stainless Steel foundation bolt
  • ASTM A193 B8 Stainless Steel flange bolts
  • SA 193 Grade B8 mushroom head square neck bolts
  • ASME SA193 Grade B8 lag bolt
  • ASME SA193 Gr B8 elevator bolt
  • A193 Grade B8 j bolt

Standards Designation
ASTM A193 B8: Class 1 Stainless Steel, AISI 304, Carbide Solution Treated.

ASTM A193 Grade B8 Stainless Steel Square Bolts Dimensions

ASTM A193 Grade B8 Heavy Hex Bolt Dimensions

ASTM A193 Grade B8 Heavy Hex Bolt Dimensions

Diameter - D   1/2 3/4 1 1 1/4 1 1/2 2 2 1/2 3
Body Diameter - D Minimum .482 .729 .976 1.223 1.47 1.964 2.461 2.961
Maximum .515 .768 1.022 1.277 1.531 2.039 2.559 3.081
Across the Flats - F Minimum .85 1.212 1.575 1.938 2.3 3.025 3.75 4.475
Maximum .875 1.25 1.625 2 2.375 3.125 3.875 4.625
Across the Corners Minimum .969 1.383 1.796 2.209 2.622 3.449 4.275 5.102
Maximum 1.01 1.443 1.876 2.309 2.742 3.608 4.474 5.34
Head Height - H Minimum .302 .455 .591 .749 .902 1.175 1.479 1.815
Maximum .364 .524 .7 .876 1.036 1.388 1.708 2.06
Thread Lengths - T > 6" 1.5 2 2.5 3 3.5 4.5 5.5 6.5
< 6" 1.25 1.75 2.25 2.75 3.25 4.25 5.25 6.25

Raw Material of ASTM A193 Grade B8

Grade Tensile Class Raw Material Description
B8 Class 1 AISI 304 Stainless Steel, Carbide Solution Treated
B8 Class 2 AISI 304 Stainless Steel, Carbide Solution Treated and Strain Hardened

ASME SA193 Grade B8 Carriage and Shoulder Bolt Torque Chart

B8 Stainless Steel Flange Bolts Torque Chart

Diameter 100% 70% 30%
Torque Torque Torque
1/2 52 36 16
9/16 75 53 23
5/8 104 73 31
3/4 184 129 55
4/8 237 166 71
1 356 249 107
1 1/8 424 297 127
1 1/4 596 417 179
1 3/8 622 435 186
1 1/2 821 574 246
1 5/8 636 445 191
1 3/4 801 561 240
1 7/8 994 696 298
2 1219 853 366
2 1/4 1762 1234 529
2 1/2 2442 1709 733
2 3/4 3285 2300 986
3 4297 3008 1289

Basic Types Of A193 B8 Threaded Rod

ASTM A193 Gr B8 Stainless Steel Heavy Hex Bolt And Nut

ASTM A193 Gr B8 Stainless Steel Heavy Hex Bolt And Nut

ASTM A193 B8 Stud Bolts

ASTM A193 B8 Stud Bolts

Astm A193 B8 Stud Bolt Thread Rod

Astm A193 B8 Stud Bolt Thread Rod

ASTM A193 grade b8 thread rod stud bolt

ASTM A193 grade b8 thread rod stud bolt

Stainless Steel Heavy Hex bolts ASTM A193 B8

Stainless Steel Heavy Hex bolts ASTM A193 B8

ASTM A193 B8 stud bolt and nut

ASTM A193 B8 stud bolt and nut

ASTM A193 B8 Hex Bolt Stud

ASTM A193 B8 Hex Bolt Stud

A193 B8 L7 PTFE Stud bolt

A193 B8 L7 PTFE Stud bolt

Standard ASTM A193 B8 2h stud bolts and nuts

Standard ASTM A193 B8 2h stud bolts and nuts

Astm A193 B8 Plain Threaded Stud Bolt

Astm A193 B8 Plain Threaded Stud Bolt

ASTM A193 B8 half thread hexagon bolt

ASTM A193 B8 half thread hexagon bolt

DIN975 B8 stud bolt round rod bar

DIN975 B8 stud bolt round rod bar

Grade 10.9 stainless steel stud bolt astm a193 gr B8 M20

Grade 10.9 stainless steel stud bolt astm a193 gr B8 M20

ASTM A193 B8 m8 stud bolt

ASTM A193 B8 m8 stud bolt

Galvanized Astm A193 B8 Threaded Bolts

Galvanized Astm A193 B8 Threaded Bolts

Grade 10.9 Galvanized ASTM A193 B8 Stud Bolt

Grade 10.9 Galvanized ASTM A193 B8 Stud Bolt

stainless steel b8 stud bolt astm a193

stainless steel b8 stud bolt astm a193

Plain ASTM A193 B8 heavy hex bolts and nuts

Plain ASTM A193 B8 heavy hex bolts and nuts

Steel Astm A193 Grade B8 Stud Bolts M28 M32 Nut Hex Cap Bolt

Steel Astm A193 Grade B8 Stud Bolts M28 M32 Nut Hex Cap Bolt

B8 ASTM A193 M16 stainless steel galvanized double tap end stud bolt

B8 ASTM A193 M16 stainless steel galvanized double tap end stud bolt


B8 Hex Nuts Size Specification

ASTM A193 B8 Screws Types A193 B8 Socket Low Head Cap Screws SA193 B8 Dog Point Socket Set Screws ASTM B8 Button Head Socket Screws A193 gr 8 Socket Head Cap Screws ASME Sa 193 b8 Cone Point Socket Set Screws SA 193 B8 Socket Head Shoulder Screws B8 Stainless Steel Plain Point Socket Set Screws ASTM A 193 GR B8 Knurled Point Socket Set Screws A193 Gr B8 Countersunk Socket Head Screws ASTM A193 Grade B8 Flange Button Head Socket Screws SA 193 Gr B8 Flat Point Socket Set Screws A193 GRB8 Taper Pressure Plug
SIZE M4 to M20 M3 to M20 M3 to M12 M1.6 to M64 M3 to M12 M6 to M24 M3 to M20 M3 to M20 M3 to M20 M3 to M10 M6 to M12 M8 to M22
ASME   B18.3.6M B18.3.4M B18.3.1 M B18.3.6M B18.3.3M B18.3.6M B18.3.6M B18.3.5M   B18.3.6M  
GRADE 10.9 45H 12.9 12.9 45H 12.9 45H 45H 12.9 12.9 45H –
ISO   4028 7380 4762 4027   4029 4029 10642   4026  

ASTM A193 Grade b8 Stainless Steel Nuts Type SIZE PROPERTY CLASS STANDARD
A193 Grade b8 Hex Nut M6 to M42 10 ISO 4032
ASTM A193 b8 Stainless Steel Nylock Nut M6 to M20 (Gr.8)
M10 to M24 (Gr.10)
8 & `10 DIN 982
A193 Gr b8 Nylock Nut M6 to M20 (Gr.8)
M10 to M24 (Gr.10)
8 & 10 DIN 985
Stainless Steel Grade b8 Hex Weld Nut M6 to M12 8 DIN 929

ASTM A193 Grade b8 Stainless Steel Washers Type SIZE (in mm) HARDNESS STANDARD
Square Section A193 Grade b8 Spring Washer 3 to 39 HV (430 to 530) DIN 7980
Flat Section ASTM A193 b8 Stainless Steel Spring Washer 3 to 39 HV (430 to 530) DIN 127 B
A193 Gr b8 Hardened Washer 12 to 30 HV (300 to 370) IS 2016
Stainless Steel Grade b8 Hardened Washer 12 to 56 Rockwell 26 to 45 (HDG)
Rockwell 38 to 45 (Coated)
ASTM F436M

Grade b8 Bolt Type SIZE PROPERTY CLASS TENSILE STRENGTH STANDARD
ASTM A193 Grade b8 Stainless Steel Hex Head Bolt / Screws M4 to M80 10.9 1040N / mm2 min ISO 4017 (Full Thread)
ISO 4014 (Half Thread)

ASTM A193 Grade b8 Hex Screw Chemical Formula

Grade Tensile Class Raw Material Description
B8 Class 1 AISI 304 Stainless Steel, Carbide Solution Treated
B8 Class 2 AISI 304 Stainless Steel, Carbide Solution Treated and Strain Hardened

Property Classes of ASME SA 193 Grade B8 Stud

Recommended Class of Nuts & Washers

Bolting Grade Nut Grade Washer Grade
ASTM A193 Grade B8 ASTM A194 Grade 8 SS 304

ASTM A193 B8 Bolts Property Class

For Bolts & Screws
  • A4-70
  • A4-80
  • F593H
  • A2-70
  • F593D
  • F593G
  • F593C
  • A2-80
For Nuts
  • F594G
  • A2-035
  • A4-70
  • A2-80
  • F594C
  • F594H
  • F594D
  • A2-70
  • A4-040
  • A4-80
For SHCS
  • F837C
  • F837
  • F837E
  • F837B
For Threaded Rods
  • B8M CL1 & CL2
  • B8
  • F593C
  • F593H
  • A2-70
  • A2-80
  • F593G
  • F593D
  • A4-80
  • A4-70

Supplier of SA 193 Gr B8 Hex Head Bolt in Mumbai, With MTC EN 10204 3.1/3.2

Stainless Steel Grade b8 Tie Bar Mechanical Properties Table

Grade B8 Class 1 B8 Class 2
Size All 1-3/8 – 1-1/2 1-1/8 – 1-1/4 7/8 – 1 Up to 3/4
Yield, min 30 ksi 50 ksi 65 ksi 80 ksi 100 ksi
Tensile, min 75 ksi 100 ksi 105 ksi 115 ksi 125 ksi
RA % min 50 45 35 35 35
Elong, %, min 30 28 20 15 12
HRC 96 max 35 max
HBW 223 max 321 max

ASME SA 193 Grade B8 Stud Torque Specs

Check below ASTM A193 Grade b8 Stainless Steel Bolt & Screw Torque which is calculated from a yield strength of 70ksi

A193 Grade b8 Bolts Nominal Diameter (in) Threads (in) Torque ft-lb (Dry) Torque ft-lb (Lubricated)
1/4″ 20 6.5 4.8
28 7.4 5.5
5/16″ 18 13.2 10.0
24 14.7 11.0
3/8″ 16 23.5 17.7
24 26.6 19.9
7/16″ 16 37.6 28.2
24 42.0 31.5
1/2″ 13 57.4 43.0
20 64.7 48.5
9/16″ 12 82.7 62.1
18 92.3 69.2
5/8″ 11 114.2 85.7
18 129.3 97.0
3/4″ 10 203 152
16 226 170
7/8″ 9 326 245
14 361 270
1″ 8 490 368
14 549 412
1-1/4″ 7 853 639
12 944 708
1-1/2″ 6 1484 639
12 1669 1252

Check below ASTM A193 Grade b8 Stainless Steel Bolt & Screw Torque which is calculated from a yield strength of 80ksi

A193 Grade b8 Bolts Nominal Diameter (in) Threads (in) Torque ft-lb (Dry) Torque ft-lb (Lubricated)
1/4″ 20 7.4 5.5
28 8.4 6.3
5/16″ 18 15.1 11.4
24 16.8 12.6
3/8″ 16 26.9 20.2
24 30.4 22.8
7/16″ 14 43.0 32.3
20 48.0 36.0
1/2″ 13 65.6 49.1
20 73.9 55.4
9/16″ 12 94.5 71.0
18 105.5 79.1
5/8″ 11 130.5 97.9
18 147.8 110.9
3/4″ 10 232 174
16 258 194
7/8″ 9 373 280
14 412 309
1″ 8 560 420
14 628 471
1-1/4″ 7 975 730
12 1079 809
1-1/2″ 6 1696 1271
12 1908 1430

Stainless Steel Grade b8 Fasteners (Nut Bolts Screw Washer) DIN and ISO designations

DIN No. 85 84 137B 94 125B 933 125A 911 127B 315 916 439B 912 939 961 931 934 960 966 963 980V 964 965 7985 975 6797A 985 6334 7991 6921 6797J 6912 ISO 7380 6923 ISO 7379
Description Slotted Pan Head Machine Screws Slotted Cheese Head Machine Screws Spring Wave Washer Cotter Pin Flat Washer (with Chamfer) Hex Head Cap Screws Fully Threaded Flat Washer (without Chamfer) Long Arm Hex Key Split Lock Washer Wing Nut Hex Socket Set Screws Machine Screws Hex Nut, Finished Hex Jam Nut Hex Socket Head Cap Screws Double End Stud Hex Head Cap Screws Fully Threaded Hex Head Cap Screws Partially Threaded Finished Hex Nut Hex Head Cap Screws Partially Threaded Phillips Oval Head Machine Screws Slotted Flat Head Machine Screws Hex Steel Prevailing Torque Lock Nut Slotted Oval Head Machine Screws Phillips Flat Head Machine Screws Phillips Pan Head Machine Screws Threaded Rod External Tooth Lock Washer Hex Nylon Insert Lock Nut Rod Coupling Nut Hex Flat Socket Head Cap Screws Hex Flange Head Screws Internal Tooth Lock Washer Hex Low Socket Head Cap Screws Hex Button Socket Head Cap Screws Hex Flange Nut Hex Socket Head Shoulder Screws

Supplier of SA 193 Gr B8 Hex Head Bolt in Mumbai, With MTC EN 10204 3.1/3.2

ANSI / ASME Standards for ASTM A193 B8 Bolts (inch series)

Small Solid Rivets ASME / ANSI B18.1.1
Square / Hex Bolts and Screws ASME / ANSI B18.2.1
Large Rivets ASME / ANSI B18.1.2
Square / Hex Nuts ASME / ANSI B18.2.2
Round Head Bolts ASME / ANSI B18.5
Socket Cap, Shoulder and Set Screws ASME / ANSI B18.3
Clevis Pins and Cotter Pins ASME / ANSI B18.8.1
Machine Screws and Machine Screws Nuts ASME / ANSI B18.6.3
Beveled Washers ASME / ANSI B18.23.1
Track Bolts and Nuts ASME / ANSI B18.10
Plow Bolts ASME / ANSI B18.9
Forged Eyebolts ASME / ANSI B18.15
Plain Washers ASME / ANSI B18.22.1
Miniature Screws ASME / ANSI B18.11
Lock Washers ASME / ANSI B18.21.1