STS Industrial - Bolts & Screws

 

A4 STAINLESS STEEL HEX HEAD CAP SCREWS

GOVERNING STANDARDS:
ISO 3506 Covers the mechanical physical properties for corrosion resistant stainless steel fasteners.
DIN 933/ISO 4017 (Full Thread) DIN 931/ISO 4014 (Partial Thread) Covers the complete general and dimensional data for metric series hex head bolts/cap screws.
ISO 6g Specifies the thread tolerance and class.

 

APPLICATIONS:

Common stainless steel fastener for general use in harsh atmospheric conditions and some corrosive environments. A4 stainless steel (equivalent to 316 stainless) has higher corrosion resistance than 18-8 stainless steel due to a higher Molybdenum content. A4 stainless steel fasteners are commonly used in applications that require general atmospheric corrosion resistance, such as chemical and food processing equipment. Some chemical environments may require special corrosion resistant materials and precautions.

MATERIAL PROPERTIES:
Austenitic Stainless Steel, AISI 316

GRADE-CLASS

DIAMETER RANGE

TENSILE STRENGTH

YIELD STRENGTH

MATERIAL MARKING

A4-50 (Soft)

≤M39

500 MPa

210 Mpa

 Grade A4-50 Stainless Steel Heax Head Bolt and Cap Screw Head Marking
A4-70 (Cold-Worked)

≤M20

700 MPa

450 MPa

 Grade A4-70 Stainless Steel Heax Head Bolt and Cap Screw Head Marking
A4-80 (High Strength)

≤M20

800 MPa

600 MPa

 Grade A4-80 Stainless Steel Heax Head Bolt and Cap Screw Head Marking
Material strengths listed are minimum acceptable per governing standard. Yield Strength based on stress at 0.2% permanent strain.
DIMENSIONAL SPECIFICATIONS:
  • DIN 931/ISO 4014 PARTIAL THREAD

    DIN 931 A4 Stainless Steel Hex Head Cap Screw Dimensions

    Usable thread length for A2 Partial Thread Hex Head Cap Screws can be approximated by the equation    THREAD LENGTH = (2 X DIAMETER) + 6mm

  • DIN 933/ISO 4017 FULLY THREADED

    DIN 933 A4 Stainless Steel Fully Threaded Hex Head Cap Screw Dimensions

Grade B bolts have looser tolerances and can be manufactured in a cold or hot-forging process. Grade A bolts are the preferred style for most applications.

Sources: ASTM Standards for Mechanical Fasteners and Related Processes 2nd Edition, Inch Fastener Standards 8th Edition, Kanebridge Fastener Reference Guide 4th 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.