This specification presents requirements for MP159 alloy bolts and shouldered studs. Minimum ultimate tensile strength is 260,000 psi (1793 MPa) at room temperature.
This specification contains the following classes. Unless otherwise specified, the requirements herein apply to all classes.
Capability: The words “shall be capable of” or “capability test” indicate characteristics or properties required in the product but for which testing of each lot is not required. However, if such testing is performed by the Purchaser, material not conforming to the requirements shall be subject to rejection.
Heat: Material traceable to a unique melt number and processing lot at the mill source, and received by the fastener supplier on a unique order number.
Process Lot: Material from the same heat that has been routed through the supplier’s plant in accordance with a set series of operations with established parameters. Identifiable by a unique number.
Purchaser: The procuring activity that issued the procurement document invoking this specification. When invoked by a U.S. Government activity, the Purchaser shall mean such activity or designee.
Supplier: Sources who provide material, parts, or services for incorporation into products.
| Element | Co | Ni | Cr | Fe | Mo | Ti | Nb | Al |
|---|---|---|---|---|---|---|---|---|
| Content (%) | 35.7 | 25.5 | 19 | 9 | 7 | 3 | 0.6 | 0.2 |
Tensile, stress rupture, and double shear tests shall be performed in accordance with a plan subject to disapproval by the Purchaser. Tensile and stress rupture tests on bolts nominally less than 3D in length, as measured from the washer face to the end of the bolt, may be taken on longer bolts, from the same heat, which have received the same processing as bolts for certification purposes. Double shear tests on bolts not meeting the dimensional test requirements of MIL-STD-1312, Test 13, need not be performed. Certification of double shear properties on such bolts shall be based on acceptance test results of the bar material from which the bolts were made.
Tensile tests shall be performed in accordance with the applicable requirements of MIL-STD-1312, Test 8, except that a two-degree wedge shall be used under the bolt head.
| Properties | MP159 | |
|---|---|---|
| RT | 1100°F | |
| UTS, ksi | 260 | 205 |
| 0.2% YS, ksi | 250 | 190 |
| Elong., % | 6 | 5 |
| RA, % | 22 | 15 |
| Requirements | MP159 |
|---|---|
| Temp./Stress/Time | 1200°F/140 ksi/23 hrs. min. |
Stress rupture tests shall be performed in accordance with the applicable requirements of ASTM E139.
Double shear tests shall be performed in accordance with the applicable requirements of MIL-STD-1312, Test 13.
Hardness tests shall be performed in accordance with the applicable requirements of MIL-STD-1312, Test Method 6, except calibration shall be as approved by the Purchaser. The tests shall be taken at the internal core of the bolt, outside of the threaded area.
| Properties | MP159 | |
|---|---|---|
| RT | 1100°F | |
| UTS, ksi | 260 | 205 |
| Requirements | MP159 |
|---|---|
| SS, ksi | 132 min. |
| Requirements | MP159 |
|---|---|
| Temp./Stress/Time | 1200°F/140 ksi/23 hrs. min. |
Must meet tensile, stress rupture, and double shear requirements.
| Thread Size |
Tensile (1) Stress-Area square inches (mm2) |
Tensile Load (2) lbf (kN) Minimum at Room Temperature |
Stress Rupture Load (3) lbf (kN) for 23-hr Min. Life at 1200°F (649°C) |
Double Shear (4) Load, lbf (kN) Minimum at R.T. |
|---|---|---|---|---|
| 0.138-32 | 0.0091 (5.8710) | 2340 (10.41) | 1365 (6.07) | 3949 (17.57) |
| 0.164-36 | 0.0147 (9.4839) | 3822 (17.00) | 2205 (9.81) | 5577 (24.81) |
| 0.190-32 | 0.0200 (12.9032) | 5200 (23.13) | 3000 (13.34) | 7485 (33.29) |
| 0.250-28 | 0.0364 (23.4838) | 9464 (42.10) | 5460 (24.29) | 12959 (57.64) |
| 0.3125-24 | 0.0580 (37.4193) | 15080 (67.08) | 8700 (38.70) | 20249 (90.07) |
| 0.375-24 | 0.0878 (56.6450) | 22828 (101.54) | 13170 (58.58) | 29158 (129.70) |
| 0.4375-20 | 0.1187 (76.5805) | 30862 (137.28) | 17805 (79.20) | 39687 (176.54) |
| 0.500-20 | 0.1599 (103.1611) | 41574 (184.93) | 23985 (106.69) | 51836 (230.58) |
| 0.5625-18 | 0.2030 (130.9675) | 52780 (234.78) | 30450 (135.45) | 65605 (291.83) |
| 0.625-18 | 0.2560 (165.1610) | 66560 (296.07) | 38400 (170.81) | 80994 (360.28) |
| 0.750-16 | 0.3730 (240.6447) | 96980 (431.39) | 55950 (248.88) | 116632 (518.81) |
Stress based on minimum diameter.
Failure allowed in shank, not head fillet.
Additional tests required if failure occurs.
| Properties | MP159 |
|---|---|
| Density | 0.302 lb./in.³ 8.37 g/cm³ |
| Melting Range | 2300 to 2525°F 1260 to 1385°C |
| Temperature | Coefficient | ||
|---|---|---|---|
| 70°F to | 21°C to | in./in./°F x 10-6 |
mm/mm/°C x 10-6 |
| 212 | 100 | 7.95 | 14.3 |
| 392 | 200 | 7.90 | 14.2 |
| 572 | 300 | 7.88 | 14.2 |
| 752 | 400 | 8.09 | 14.6 |
| 932 | 500 | 8.29 | 14.9 |
| 1112 | 600 | 8.39 | 15.1 |
| 1292 | 700 | 8.90 | 16.0 |
| 1472 | 800 | 10.13 | 18.2 |
| Temperature | psi x 106 (Mpa x 103) | ||
|---|---|---|---|
| °F | °C | Annealed | Cold Worked and Aged |
| 78 | 26 | 32.2 (222) | 35.3 (243) |
| 450 | 232 | 30.2 (211) | 32.8 (226) |
| 900 | 482 | 27.1 (187) | 29.3 (202) |
| Temperature | psi x 106 (Mpa x 103) | ||
|---|---|---|---|
| °F | °C | Annealed | Cold Worked and Aged |
| 78 | 26 | 11.7 (81) | 11.3 (78) |
| 450 | 232 | 11..0 (76) | 10.5 (72) |
| 900 | 482 | 9.9 (68) | 9.4 (65) |
The requirements of P2TF1, CL-A, shall be complied with. The material(s) shown below were referenced in this specification and P2TF1, CL-A, as of the date of this specification issue. The list below does not include all materials which are referenced in sub-tier documents.
The following documents form a part of this specification. Unless otherwise indicated, the latest issue shall apply.
Material shall be procured only from sources approved by the Purchaser.
Bolts shall be made from a nickel-cobalt base alloy known as MP159.
Material supplied to this specification shall meet the chemical composition requirements of AMS 5842.
The analysis made by the melter to determine the percentage of elements required by this specification shall conform to the requirements of 3.2.1 and shall be reported in the forger’s certificate of test.
Material supplied to this specification shall be produced by vacuum induction melting followed by vacuum consumable electrode remelting.
Material supplied to this specification shall be uniform in quality and condition, clean, sound, free from foreign materials, and from internal and external defects detrimental to fabrication or performance of parts.
Suppliers shall maintain a controlled document with effective controls for each step of the processing sequence. The document shall be subject to approval by the Purchaser. Significant process parameters shall be identified along with their corresponding control points and control limits (within engineering requirement limits). Process parameter measurements shall be made at the control points, and modification plans shall be defined for control limit violations. Frequency of control point monitoring shall also be identified.
Formed by hot or cold upsetting.
All heat treat temperatures refer to metal temperature ±25°F (±14°C). All times refer to time at temperature for the heaviest section.
After upsetting, blanks shall be aged, then ground and thread rolled. Aging temperature: 1200°F–1250°F for 4 hours.
Washer face, shank, and areas to be threaded shall be ground to remove all surface contamination and decarburized layers. Grinding or alternate machining methods are to be used to ensure losses are controlled within dimensional tolerances. Parts may have stock removal up to a maximum of: 0.002 inch (0.05 mm) from the shank diameter after all processing and heat treatments. Grinding or alternate machining methods shall be as approved by the Purchaser.
Class A threads: fully formed by a single cold rolling process after grinding, but before aging (historical reference) Class B threads: fully formed by a single cold rolling process after aging and grinding
All fillet radii, head-to-shank, or shear and machine bolts, shoulder-to-shank of shouldered studs shall be cold worked by rolling after completion of the aging treatment. Cold working shall remove all visual evidence of grinding or tool marks.
Distortion due to cold working shall not raise metal more than: 0.002 inch (0.051 mm) above the contour at “A”, or depress metal more than 0.002 inch (0.051 mm) below the contour at “B”, as shown in Figure 1. Distorted areas shall not extend beyond “C”, as shown in Figure 1.
The shank diameter shall be as shown on the engineering drawing except in the regions where enlargement has occurred because of displacement of metal during cold rolling of the fillet radius. The size of the displaced metal shall be in accordance with 3.3.6.1 and Figure 1.
The bearing surface shall be as defined on the engineering drawing except in the regions where cold rolling of the fillet radius has displaced metal affecting the bearing surface. The size of the displaced metal shall be in accordance with 3.3.6.1 and Figure 1.
Parts shall be hardness tested and shall have a minimum hardness of Rockwell C 44 or equivalent in accordance with ASTM E140.
Flow lines on heads of parts shall follow the contour of the shank, head to shank fillet, and bearing surface as shown in Figure 2a. Slight cutting of flow lines is permissible as shown in Figure 2b. Excessive cutting of flow lines in the shank, head to shank fillet, and bearing surface is not permissible as shown in Figure 3.
The grain flow in the threads shall be continuous and shall follow the general thread contour with the maximum density at the bottom of the root radius as shown in Figure 4.
The total intergranular attack and alloy depletion shall not extend to a depth greater than 0.0005 inch (0.013 mm) on any portion of the threaded bolt except nonbearing areas of the head and the first incomplete thread and chamfer on the lead end of the bolt.
Thread forms shall conform to MIL-S-8879.
The entering end of external threads may be outside the specified limits of size for a length not to exceed two pitches, including chamfer.
There shall be a minimum thread run-out of one thread and a maximum of two threads. The run-out shall fair onto the shank to eliminate an abrupt change in cross-sectional area. Bottom and sides of threads contained in run-out shall be filleted smooth and shall be devoid of abrupt tool stop marks.
Root imperfections such as laps, seams, notches, slivers, folds, roughness, or oxide scale are not permissible as shown in Figure 5.
Single laps shall conform to the following:
Slight deviations from thread contour are permissible at the crest of the thread within the major diameter limits as shown in Figure 9 and at the incomplete thread at each end of the threaded section.
Specimens shall be taken from the finished part as shown in Figure 10 and processed in accordance with 4.2 and shall meet the requirements stated herein.
After completion of all processing and cleaning operations and immediately before plating (if applicable), parts shall be fluorescent penetrant inspected in accordance with 4.3, and shall conform to the following acceptability limits:
The Supplier shall certify all chemical and mechanical tests herein specified. This certificate shall report results of all tests performed and show that the results are in accordance with the requirements of this specification. If a heat appears in more than one lot of parts, the numerical results of the tests shall be recorded in the certificate of test for each of the lots of parts in which it appears. In addition, the certificate shall contain the following information:
Chemical analyses shall be performed in accordance with ASTM standards or methods approved by the Purchaser.
Chemical check analysis limits shall be in accordance with AMS 2269.
Specimens shall be taken from the finished part as shown in Figure 10, and examined for conformance to specification requirements. Inspection for conformance to thread, head lap and IGA requirements shall be performed in the unetched condition. Magnification and etching condition shall be as follows:
Fluorescent penetrant inspection shall be performed in accordance with P3TF2, CL-D.
All material shall be packed to prevent damage, loss or contamination during handling, shipping or storage.
Each shipment shall be legibly marked with the purchase order number, Supplier's name, quantity, part name, drawing number, and this GE specification number, class, and issue number.
This is not a requirement but is furnished as an index to those paragraphs that have been classified: