مهره A 194 و استاندارد های آن | ASTM A194

استاندارد ASTM A194  شامل مهره های کربنی ، آلیاژ و فولااد ضد زنگ هستند که برای شرایط با فشار یا دمای بالا در نظر گرفته می شود.

در جداول پایین کلاس ها و مشخصات مکانیکی و شیمیایی انواع مهره های ASTM A194  بطور کامل ذکر شده اند.

 کلاس های مهره A194 

2Carbon steel heavy hex nuts
2HQuenched & tempered carbon steel heavy hex nuts
2HMQuenched & tempered carbon steel heavy hex nuts, 100% hardness tested
4Quenched & tempered carbon-molybdenum heavy hex nuts (withdrawn in 2017)
7Quenched & tempered alloy steel heavy hex nuts
7MQuenched & tempered alloy steel heavy hex nuts, 100% hardness tested
7LQuenched & tempered alloy steel heavy hex nuts, Charpy impact tested
8Stainless AISI 304 heavy hex nuts
8MStainless AISI 316 heavy hex nuts

 

خواص مکانیکی مهره A 194

A194 Mechanical Properties

Grade Identification Marking5SpecificationMaterialNominal Size, In.Tempering Temp. °FProof Load Stress, ksiHardness RockwellSee Note
MinMax
2ASTM A194 Grade 2Medium Carbon Steel1/4 – 401501593521,2,3
2HASTM A194 Grade 2HMedium Carbon Steel, Quenched and Tempered1/4 – 4850175C24C381,2
2HMASTM A194 Grade 2HMMedium Carbon Steel, Quenched and Tempered1/4 – 411501501592371,2,3
4ASTM A194 Grade 4Medium Carbon Alloy Steel, Quenched and Tempered1/4 – 41100175C24C381,2
7ASTM A194 Grade 7Medium Carbon Alloy Steel, Quenched and Tempered1/4 – 41100175C24C381,2
7MASTM A194 Grade 7MMedium Carbon Alloy Steel, Quenched and Tempered1/4 – 411501501592371,2,3
8ASTM A194 Grade 8Stainless AISI 3041/4 – 4801263004
8MASTM A194 Grade 8MStainless AISI 3161/4 – 4801263004

NOTES 

  1. The markings shown for all grades of A194 nuts are for cold formed and hot forged nuts. When nuts are machined from bar stock, the nut must additionally be marked with the letter ‘B’. The letters H and M indicate heat treated nuts.
  2. Properties shown are those of coarse and 8-pitch thread heavy hex nuts.
  3. Hardness numbers are Brinell Hardness.
  4. Nuts that are carbide-solution treated require additional letter A – 8A or 8MA.
  5. All nuts shall bear the manufacturer’s identification mark. Nuts shall be legibly marked on one face to indicate the grade and process of the manufacturer. Marking of wrench flats or bearing surfaces is not permitted unless agreed upon between manufacturer and purchaser.
  6. Other less common grades exist, but are not listed here.

 Inch Fastener Standards. 7th ed. Cleveland: Industrial Fasteners Institute, 2003. N-80 – N-81.

خواص شیمیایی مهره های A 194

A194 Chemical Properties

Element2, 2H, and 2HM47 and 7M (AISI 4140)8 (AISI 304)8M (AISI 316)
Carbon0.40% min0.40 – 0.50%0.37 – 0.49%0.08% max0.08% max
Manganese1.00% max0.70 – 0.90%0.65 – 1.10%2.00% max2.00% max
Phosphorus, max0.040%0.035%0.035%0.045%0.045%
Sulfur, max0.050%0.040%0.040%0.030%0.030%
Silicon0.40% max0.15 – 0.35%0.15 – 0.35%1.00% max1.00% max
Chromium  0.75 – 1.20%18.0 – 20.0%16.0 – 18.0%
Nickel   8.0 – 11.0%10.0 – 14.0%
Molybdenum 0.20 – 0.30%0.15 – 0.25% 2.00 – 3.00%