ASTM-A453-Grade-660-Class-A-Stud Bolts-hex-nuts

ASTM A453 Grde 660 Class A stud bolts A453 Grade 660A Hex nuts

ASTM A453 Grde 660 Class A Fasteners Manufacturer

Grade 660 Class A Stud Bolt ,also known as Grade 660 A Stud bolt,refers to a specific type Class A of grade 660 under ASTM A453 Standard,which is a high-temperature, high-strength fastener used in critical applications such as pressure vessels, valves, flanges, and heat exchangers—particularly in the petrochemical, power generation, and aerospace industries.

Equivalent Materials of A453 grade 660 Class A

  • UNS S66286 (A-286)
  • Werkstoff 1.4980
  • DIN X5NiCrTi26-15

A453 grade 660 Class A stud bolts are produced from High quality ASTM A453 Grade 660 Round bar.

  • Diameter Range (Nominal):
    • Metric: M6 through M64 (common commercially)
    • Imperial (inch): ¼″ – 4″ (¼″, 5⁄16″, 3⁄8″, 7⁄16″, ½″, 5⁄8″, ¾″, 7⁄8″, 1″, 1 1⁄8″, 1 ¼″, 1 ½″, 1 ¾″, 2″,2 1/2″,3″,3 1/2″,4″)
  • Length Range:Typically 20 mm up to 1000 mm

ASTM A453 Grade 660 Class A Stud Bolt

SpecificationDetails
StandardASTM A453
Grade660
ClassA
Material TypePrecipitation-hardened austenitic stainless steel
Common FormsStud bolts, threaded rods, nuts
Temperature RangeSuitable for high-temperature service up to 815°C (1500°F)
SurfacePlain finishing or PTFE Coating/Xylan Coating
ASTM A453 Grade 660 A Chemical Composition Limits
Weight%CMnPSSiCrNiMoTiVAlBCoCu
ASTM A453 GR.6600.08 max2 max0.025 max0.025 max1 max13.5-1624-271-1.51.9-2.350.10-0.500.35 max0.0003-0.0101 max0.50 max

Mechanical Properties of ATSTM A453 Grade 660 Class A

PropertyValue
Tensile Strength125 ksi (860 MPa)
Yield Strength (0.2% offset)105 ksi (725 MPa)
Elongation (in 4D)15%
Reduction of Area30%
Hardness248-341 HBW
ASTM A453 Grade 660 Class A Stud Bolt

How do we make the ASTM A453 Grade 660 Class A stud bolts and quality Control

Producing ASTM A453 Grade 660 Class A stud bolts involves precise manufacturing processes and stringent quality control (QC) to meet high-temperature, high-strength requirements.

A typical Inspection and test plan for ASTM A453 Grade 660 Class A stud bolt.

NoActivity / OperationCharacteristics / DescriptionReference StandardInspection / Test MethodAcceptance CriteriaResponsibility
1 Raw Material InspectionChemical & mechanical certification, traceabilityASTM A453, EN 10204Visual + MTC verificationAs per ASTM A453QA/QC
2Material IdentificationPMI (Positive Material Identification)　XRF / OESConfirm alloy gradeQA/QC
3 CuttingSize check, heat number transferManufacturer SOPVisual, measuring toolsDimensional toleranceProduction
4Heat TreatmentSolution annealing + agingASTM A453Heat treatment recordTime/Temp per Class AQA/QC
5ThreadingPitch, major/minor diameter, lengthASME B1.1 / B1.13MThread gauge, calipers± toleranceQA/QC
6 Dimensional InspectionFull body and thread dimensionsDrawing / Purchase SpecVernier, micrometer, gaugeWithin toleranceQA/QC
7Chemical composition TestingChemical composition TestingASTM A453 Grade 660　ASTM A453 Grade 660QA/QC
8Mechanical TestingTensile, yield, elongation, RAASTM A370 / A453UTMMin: 860 MPa UTS, 725 MPa YSThird Party / QA/QC
9Hardness TestBrinell or RockwellASTM E18Hardness tester248- 341 HBWQA/QC
10 Surface Finish & CoatingCleanliness, plating thickness (if coated)　Visual, micrometerUniform, crack-freeQA/QC
11MarkingGrade, Heat No., Manufacturer IDASTM A453VisualPermanent and legibleQA/QC
12Final InspectionVisual, dimensional, traceabilityPurchase Order / SpecVisual + MeasurementAll OKQA/QC + Client

Difference between ASTM A453 Grade 660 Class A and Class B

All classes (A, B, C, D) of ASTM A453 Gr 660 use the same base material (precipitation-hardened austenitic stainless steel, UNS S66286), but they are difference in their heat treatment cycles and mechanical property targets.

ASTM A453 Grade 660 – Class A vs. Class B
PropertyClass AClass B
Tensile Strength (min)860 MPa (125 ksi)965 MPa (140 ksi)
Yield Strength, 0.2% offset (min)725 MPa (105 ksi)860 MPa (125 ksi)
Elongation in 4D (min)15%15%
Reduction of Area (min)30%25%
Hardness (max)248-341 HBW (~37 HRC)248-341 HBW (~37 HRC)
Heat TreatmentSolution annealed + aged for lower strengthSolution annealed + aged for higher strength
ApplicationsGeneral high-temperature boltingHigher-load, critical-temperature bolting
DuctilityHigherLower than Class A (due to increased strength)

How to chose the right material grade

Which grade is good for your application,ASTM A453 Grade 660 Class A or ASTM A453 Grade 660 Class B Stud bolt

ClassBest for
ASTM A453 Grade 660 Class AApplications where moderate strength and better ductility are desired (e.g., pressure vessels, some turbine cases).
ASTM A453 Grade 660 Class BApplications requiring higher strength but with reduced ductility, often in more critical or space-constrained bolted joints.

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