 |
|||
|
|
|||
| ||||||||||
|
|  MIL-S-45387B(AT)
as-quench minimum hardness of Rockwell C55 at the half-radius of the finished bar body when
processed in accordance with the torsion bar manufacturers actual production procedure
*
3.4 Construction. The spring construction shall conform to the requirements specified on
applicable drawings.
3.5 Processing.
3.5.1 Forming. Ends of springs shall be formed by upsetting to provide a continuous,
uniform grain flow that conforms to the blend surfaces of the finished spring. Grain flow shall not
terminate into blend radii. The serrated ends shall be either cold formed, hobbed or form ground.
*
3.5.2 Heat treatment. The treatment selected shall be capable of meeting the hardness
specified herein or on applicable drawing. Unless otherwise specified, when the material is steel, the
springs shall be quenched and tempered to a hardness of Rockwell C47-51 from the half radius to the
outside of the finished bar body. The hardness may be as low as Rockwell C45 from the half radius
to the center, provided that the total spread of hardness in any one cross section shall not exceed five
(5) points Rockwell C. Microscopic examination of polished and/or etched cross section of springs
shall verify absence of abnormal surface condition that may result from heat treatment.
Decarburization and retained austenite, as determined by microscopic examination at a magnification
of 250 diameters shall not be permissible on steel springs.
3.5.2.1 Reprocessing. The torsion bar springs represented by the bar failing to meet
endurance requirements may be reheat treated providing the material and dimensional requirements
specified herein are complied with. The bars shall be reprocessed in accordance with the process
used in production (see 6.2). Reprocessed bars shall be from an identifiable heat. Under no
circumstance shall any bars from another heat of steel previously rejected be reprocessed and
resubmitted as part of any other heat.
3.5.3 Straightening. All straightening operations after final heat treating shall be performed
with the spring held at a temperature of not less than 600F.
*
3.5.4 Surface indications and discontinuities. Springs shall show no evidence of
circumferential or longitudinal indications of cracks or heavy seams except that light longitudinal
indications less than four (4) inches in length, which can be completely polished and blended with
surface by the removal of 0.010 inch or less material are permissible.
*
3.5.5 Shot peening. Springs shall be shot peened in accordance with MIL-S-13165 to a
minimum peening intensity of 0.010C for the body and 0.007C for the serrations and to a minimum
visual surface coverage of one hundred (100) percent. Diameter of shot used on body shall be
0.035 to 0.064 inch and on the serrations 0.017 to 0.033 inch. Body and serrations may be peened
3
|
|
Privacy Statement - Press Release - Copyright Information. - Contact Us |
Click
here for thousands of PDF manuals