SAE AMS 7301G pdf download
SAE AMS 7301G pdf download.Steel,Highly-Stressed Springs0.95Cr – 0.2ov (0.48- 0.53C)(SAE 6150) Case Hardened.
1.1 Form:
This specification covers low-alloy steel springs made of annealed round wire heat treated after forming.
1.2 Application:
These springs have been used typically for valve springs, clutch springs, and other highly-stressed springs on which a hardened case is required as assurance that surfaces will not be decarburized, but usage is not limited to such applications. Hardness of these springs is very high and use is recommended only after careful consideration.
2. APPLICABLE DOCUMENTS:
The issue of the foflowing documents in effect on the date of the purchase order forms a part of this specification to the extent specified herein. The supplier may work to a subsequent revision of a document unless a specific document issue is specified. When the referenced document has been canceled and no superseding document has been specified, the last published issue of that document shall apply.
2.1 SAE Publications:
Available from SAE, 400 Commonwealth Drive, Warrendale, PA 15096-0001 or www.sae.org.
AMS 2259 Chemical Check Analysis Limits, Wrought Low-Alloy and Carbon Steels AMS 2301 Steel Cleanliness, Aircraft Quality, Magnetic Particle Inspection Procedure AMS 2370 Quality Assurance Sampling and Testing, Carbon and Low-Alloy Steel Wrought
Products and Forging Stock
3.3.3 Metal shall not be removed from any active coil.
3.3.4 Springs shall be heat treated by carburizing, cyaniding, or carbonitriding above the transformation range of the steel, quenching, and tempering. All possible care shall be exercised during heat treatment to prevent surface and internal cracking.
3.3.5 After heat treatment, springs shall be uniformly blasted all over, with grit of suitable size, for such time and in such manner as will produce springs which are satisfactorily cleaned and on which the surface effect Is not deeper than that agreed upon by purchaser and vendor.
3.3.6 Grit blasted springs shall subsequently be uniformly blasted, preferably in automatic equipment, with sand of suitable size, for sufficient time to produce smooth surfaces.
3.4 Properties:
Springs shall conform to the following requirements:
3.4.1 Hardness: Core hardness of springs shall be 65 to 69 HR3ON, or equivalent (See 8.2), determined in accordance with ASTM E 18.
3.4.2 Average Grain Size: Shall be ASTM No. 5 or finer, determined in accordance with ASTM E 112.
Case Depth: Shall be 0.001 to 0.005 inch (0.03 to 0.13 mm) on springs, determined on a cross- section mounted, polished, etched in nital for sufficient time to develop a well-defined microstructure, and examined at a minimum of 100X magnification.
3.4.4 Decarburization: Springs shall be free from partial and complete decarbunzation, determined as in
3.4.3. Examination for decarburization may be made on the same specimens on which case depth was determined.
3.45 Bending:
3.4.5.1 Specimens cut from finished springs shall, as evidence of the presence of case, fracture before the angle of bend reaches 180 degrees. The bend shall be made in accordance with ASTM E 290 around a diameter equal to twice the nominal diameter of the wire with the 00 of the spring on the inside of the bend.
3.4.5.2 Sections of springs, or specimens of the wire processed in the same manner as springs, shall, as evidence of ductility of the springs, withstand, without cracking, bending at room temperature through an angle, measured under load, of 5 degrees. Bend shall be made as described in 3.4.5,1.
3.5 Quality:
Wire and finished springs shall be uniform in quality and condition, clean, sound and free from foreign materials and from imperfections detrimental to usage of the wire and springs.
