1、MIES-70703 12 January 1987 MILITARY SPECIFICATION STRAND CAST STEEL, CAFIEON AND ALLOY, RIR PROJECTILE APPLICATIONS This specification is approved for use within US Army, Armament, Munitions and Chemical Command, and is available for use by all Departments and Agencies of the Department of Defense.
2、1. SCOPE 1.1 Scope. This specification covers the strand cast process for manufacturing hot-rolled carbon and alloy steel for projectile applications. The requirements of this specification supplement existing material specification requirements on individual. projectile metal parts drawings when th
3、e steel being furnished is made by the strand cast process. 1.2 Classification. Strand casting process, equipment and reduction ratios shall be in accordance with the following classes and types as specified ( see 6.2) : Class I - Steel made using submerged ceramic shrouding from tundish to mold. Cl
4、ass II - Steel made using a centrifugal caster. Class III - Steel made using either submerged ceramic shrouding or gaseous type shrouding from tundish to mold. TypeA - TypeB - Steel rolled to a 4 to 1 minimum reduction ratio. Steel rolled to a 2.5 to 1 minimum reduction ratio. Beneficial comments (r
5、ecommendations, additions, deletions) and any pertinent data which may be of use in improving this document, should be addressed to: Commander, US Army Armament, Research and Development Center, ATTN: SMCAR-ESC-AS, Dover, New Jersey 07801-5001 by using the self-addressed Standardization Document Imp
6、rovement Proposal (DD Form 1426) appearing at the end of this document or by letter. / . I, c7 THIS DOCUMENT CONTAINS /e PAGES. AYSC NIA MECA DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited. Licensed by Information Handling Services- MIL-S-70703 HE m 9999906 0122590
7、m Mnrs-70703 2. APPLICABm D0cUME“pS 2.1 Specifications, standards and handbooks. This paragraph is not applicable to this.specification. 2.2 Other publications. specification to the extent specified herein. which are indicated as DoD adopted shall be the issue listed in the current DoDISS and the su
8、pplement thereto, if applicable. The following documents form a part of this The issues of the documents ASTM ASIIM E381 - Macroetch Testing, Inspection, and Rating Steel Products, Comprising Bars, Billets, Blooms, Method Of (Application for copies should be addressed to MIM, 1916 Race Street, Phila
9、delphia, PA 1 91 03) Society of Automotive Engineers SAE 5422 - Microscopic Determination of Inclusions in Steels, Recommended Practice (Application for copies of SAE publications should be addressed to the Society of Automotive Engineers, 40 Commonwealth Dr, Warrendale, Pa. 150%) American Iron and
10、Steel Institute (AISI) AISI Steel Products Manual - Alloy, Carbon and High Strength, Low Alloy Steel, Semi-finished for Forging, Hot Rolled Bars, Cold Finished Bars, Hot Rolled Deformed and Plain Carbon Reinforcing Bars. (Application for copies should be addressed to the American Iron and Steel Inst
11、itute, loo0 - 16th Street NW, Washington, DC 20036) (Industry association specifications and standards are generay available for reference from libraries. They are also distributed among technical groups and using Federal Agencies). 2.3 Order of precedence. In the event of a conflict between the tex
12、t of this specification and the references cited herein, the text of this specification shall take precedence. 3.1 Process. 3. I .I Classes. 3.1 .I .I Class I. 3.1 .I .I .I Shrouding. A submerged ceramic shroud or a “box type“ gaseous shroud is required from the ladle to the tundish. shrouding is re
13、quired from the tundish to the mold. Submerged ceramic Adequate sealing is .+. . .- F c Licensed by Information Handling ServicesMIL-S-70703 ME m 999990b 0122571 b m a 1 F e * MILS-70703 required at all shrouding couplings to insure the prevention of atmospheric air aspiration. adequate to assure pr
14、oper residual time, promote inclusion flotation, and minimize turbulence. 3.1.1.1.2 Tundish. The size and design of the tundish shall be 3.1.1.1.3 Computer control. Computer control of casting variables such as casting speed, mold oscillation and stroke, secondary cooling spray pressures and flows,
15、etc. is preferred. When computer control is not available, data shall be monitored and recorded for these process variables,and the process variables to be monitored and the frequency of recording shall be submitted to the cognizant Government contracting officer for approval. 3.1.1.2 Class II. Clas
16、s II steel is produced by a centrifugal mold caster. With the exception of the tundish-twmold submerged ceramic shroud requirement, Class II steel must be produced using equipment and procedures which meet all of the requirements listed above for Class I steel. 3.1.1.3 Class III: 3.1.1.3.1 Shroud, l
17、adle to tundish. Either a submerged ceramic shroud or a “box-type“ gaseous shroud is required from the ladle to the tundish. Adequate sealing is required at al1 shrouding couplings to insure the prevention of atmospheric aspiration. 3.1.1.3.2 Shroud, tundish to mold. Either submerged ceramic or gase
18、ous shroud is required from the tundish to the mold. the oxygen levels in the vicinity of the molten stream must be monitored and shall be below 0.5%. that all critical variables associated with the operation of gaseous shrouds are being monitored and recorded periodically during the casting operati
19、on. As a minimum , oxygen levels shall be measured at the beginning and end of each heat and at approximately the 1 /4,1/2 and 3/4 intervals during casting of each heat. This is particularly critical, because consistency of operation is imperative when using any gaseous shrouding system. adequate to
20、 consistently produce material meeting the internal quality requirements specified herein. Por gaseous shroud systems, Adequate control systems must be in place to assure 3.1.1.3.3 Tundish. The size and design of the tundish should be 3.1.2 Reduction ratio. Reduction ratios shall be in accordance wi
21、th that specified for Type A or B, as specified. 3.1.3 Deoxidizers and grain refiners. Deoxidizers and grain refiners shall be ladle added. individual strand molds of the tundish is prohibited. Wire feeding of these additions directly into 3.1.4 Oxygen lancing. Oxygen lancing to open clogged tundish
22、 nozzles is permitted only when the steelmaker has demonstrated the ability to locate and discard all steel affected by the process. 3.1.5 Ladle stirring. bile stirring for chemical homogeneity, uniformity of temperature and to promote flotation of the inclusions is required. Licensed by Information
23、 Handling ServicesMIL-S-70703 ME 777770b 0322572 W MILS-70703 3.1.6 Slag cover. With the exception of initial casts, until the tundish is full, the tundish shall have a slag cover at all times. 3.1.7 Sequence casting. When sequence casting heats of different grades, transition material. between the
24、two grades of steel shaU not be mnished under this specification. 3.2 Material soundness. Imperfections observable in strand cast steel are illustrated in Figure 1. Using Figure 1 as reference guidance, strand cast steel sMl conform to the material sounness requirement specified herein. 10 I 5 / Fig
25、ure 1. Potential imperfections in continuous cast steel. 1. Halfway Cracks 7. Longitudinal Facial Crack 2. Hinge Cracks 8. Longitudinal Corner Crack 3. Diagonal Cracks 9. Pinholes 4. Subsurface Blowholes/Pinpoints 10. Center Rupture 5. Transverse Facial Crack 11. Centerline (Star) Cracks 6. Transver
26、se Corner Crack Licensed by Information Handling ServicesMIL-S-70703 ME = 7777706 OXZ25FKTFE a I a a MILS-70703 3.2.1 3.2.1.1 As cast macroetch (see 4.2.4 i.e., all bars and billets shall conform to the appropriate tolerances as contained in referenced material specifications and AIS1 steel product
27、manual. 4. QUALITY ASSITRANCE PROVISIONS 4.1 Responsibility for inspection. Unless otherwise specified in the contract or purchase order, the supplier is responsible for the performance of all inspection requirements as specified herein. specified in the contract or purchase order, the supplier may
28、use his own or any other facilities suitable for the performance of the inspection requirements specified herein, uness disapproved by the Government. Government reserves the right to perform any of the inspections set forth in the. specification where such inspections are deemed necessary to assure
29、 supplies and services conform to prescribed requirements. Except as otherwise The Licensed by Information Handling ServicesMIL-S-70703 NE W 7777706 0122575 3 W MILS-70703 4.1.1 Responsibility for compliance. All material must meet all reauirements of Section 3. The inspection set forth in this spec
30、ification shkl become a part of the contractrs overall inspection system or qdity program. shall not relieve the contractor of the responsibility of assuring that all products or supplies submitted to the Government for acceptance comply with all requirements of the contract. Sampling in quality con
31、formance does not authorize submission of known defective material, either indicated or actual, nor does it commit the Government to acceptance of defective material. The absence of any inspection requirements in the specification 4.2 Sampling. 4.2.1 Transverse sections (as cast) . Transverse sectio
32、ns representing the entire strand cast section shall be cut from the front and back of each heat in the as-cast condition for macroetching. 4.2.2 Macroetch sections (finished product). Macroetch sections shall be taken from the front. middle. and last rolled product after final reduction from each s
33、tr 763 1.770 1.777 1.784 1.791 1.798 1.805 1.812 1.819 1.826 1.833 1.840 1.847 1.854 1.861 1.868 1.875 1.882 1.889 1.896 1.903 1.910 1.917 1.924 1.931 - APPENDIX Ni MIL-S-70703 Cr - - 1.327 2.944 1.331 2.966 1.334 2.987 1.338 3.009 1.343 3.030 1.345 3.052 1.349 3.074 1.352 3.095 1.356 3.117 1.360 3.
34、138 1.364 3.160 1.367 3.182 1.370 3.203 1.375 3.225 1.378 3.246 1.383 3.268 1.386 3.290 1.389 3.311 1.393 3.333 1.396 3.354 1.400 3.376 1.403 3.398 1.406 3.419 1.411 3.441 1.414 3.462 1.418 3.484 1.422 3.506 1.426 3.527 1.429 3.549 1.433 3.570 1.437 3.592 1.440 3.614 1444 3.635 1.447 3.657 1.450 3.6
35、78 1.454 3.700 1.458 3.722 1.461 3.743 1.465 3.765 1.470 3.786 1.473 3.808 1.476 3.830 . 1.481 3.851 1.484 3.873 1.938 1.487 3.894 TBLE 1, HARDENABILITY FACTORS (CONT D) 11 4 Licensed by Information Handling ServicesMIL-S-70703 NE W 7777706 0122b03 7 W % Alloy 1.35 1.36 1.37 1.38 1.39 1.40 1.41 1.42
36、 1.43 1.44 1.45 1.46 1.47 1.48 1.49 1.50 1.51 1.52 1.53 1.54 1.55 1.56 1.57 1.58 1.59 1.60 1.61 1.62 1.63 1.64 1.65 1.66 1.67 1.68 1.69 1.70 1.71 1.72 1.73 1.74 1.75 1.76 1.77 1.78 1.79 1.80 Mn 5 s.765 - 5.816 5.867 5.918 5.969 6.020 6.071 6.122 6.173 6.224 6.275 6.326 6.377 6.428 6.479 6.530 6.581
37、6.632 6.683 6.734 6.785 6.836 6.887 6.938 6.989 7.040 7.091 7.142 7.193 7.224 7.295 7.346 7.397 7.448 7.499 7.550 7.601 7.652 7.703 7.754 7.805 7.856 7.907 7.958 8.009 8.060 Si 1 .-945 1.952 1.959 1.973 - 1 e.966 1.980 1.987 1.994 2.001 2.008 2.015 2.022 2.029 2.036 2.043 2.050 2.057 2.064 2.071 2.0
38、78 2.085 2.092 2.099 2.106 2.113 2.120 2.127 2.134 2.141 2.148 2.155 2.162 2.169 2.176 2.183 2.190 2.197 2.204 2.211 2.218 2.225 2.232 2.239 2.246 2.253 2.260 APPENDIX MIL-S-70703 Cr - Ni - 1.491 3.916 1-.495 3.938 1.498 3.959 1.501 3.981 1.506 4.002 1.509 4.024 1.512 4.046 1.517 4.067 1.520 4.089 1
39、523 4.110 1.527 4.132 1.531 4.154 1.535 4.175 1.538 4.197 1.541 4.217 1.545 4.239 1.556 4.262 1.561 4.283 1.565 4.305 1.569 4.326 1.574 4.348 1.578 4.369 1.582 4.391 1.586 4.413 1.591 4.434 1.595 4.456 1.600 4.478 1.604 4.499 1.609 4.521 1.613 4.542 1.618 4.564 1.622 4.586 1.627 4.607 1.631 4.629 1.
40、636 4.650 1.640 4.672 1.644 4.694 1.648 4.715 1.652 4.737 1.656 4.759 1.660 4.780 1.664 1.668 1.672 1.676 1.680 15 Licensed by Information Handling Services% Alloy 1.81 1.82 1.83 1.84 1.85 1.86 1.87 1.88 1.89 1.90 1.91 1.92 1.93 1.94 1.95 Mn 8.111 8.162 8.213 8.315 8.366 - 8.417 8.468 8.519 8.570 8.
41、621 8.672 .8.723 8.774 8.825 8.876 1.96 1.97 1.98 1.99 2.00 APPENDIX MIL- S- 7 0703 Si 2.267 2.274 2.281 2.288 2.295 - 2.302 2.309 2.316 2.323 2.330 2.337 2.344 2.351 2.358 2.364 2.372 2.379 2.386 2.393 2.400 Ni 1.687 1.694 1.701 1.708 1.715 1.722 1.729 1.736 1.743 1.750 - 1.753 1.756 1.759 1.761 1.765 1.767 1.770 1.773 1.776 1.779“ *Nickel Over 2%: Factor = 1.00 -b .333 (% Ni) + .O66 (% Ni)2 - ,055 (% Ni)3 + .O18 (% Ni)4 TABLE I. HARDENABILITY FACTORS U Licensed by Information Handling Services
