1、/%y- os”c3 6 DOD-STD-2188(SH) 1 April 1987 SUPERSEDING NAVSEA 0283-LP-228-1000 May 1961 MILITARY STANDARD BABBITTING OF BEARING SHELLS (METRIC) AMSC N/A FSC 3120 DISTRIBUTION STATEMENT A Approved for public release; distribution unlimited f THIS DOCUMENT CONTAINS PAGES. Provided by IHSNot for Resale
2、No reproduction or networking permitted without license from IHS-,-,-DOD-STD-2188 (SH) 1 April 1987 BEPARTNENT OF THE NAVY NAVAL SEA SYSTENS COMMAND Washington, DC 20362-5101 Babbitting of Bearing Shells 1. This Military Standard is approved for use by the Naval Sea Systems Command, Department sf th
3、e Navy, and is available for use by all Departments and Agencies of the Department of Defense. 2. Beneficial comments (recommendations, additions, deletions) and any perti- $ nent data which may be of use in improving this document should be addressed to: Commander, Naval Sea Systems Command, SEA 55
4、23, Department of the Navy, I Washington, DC 20362-5101 by using the self -addressed Standardization Dscument Improvement Proposal (DD Form 1426) appearing at the end of this document or by letter, Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-a P-
5、 - FOREWORD 1. Babbitted bearings are widely used in applications that are not subjected to large reciprocating loads or elevated temperatures. In Naval ships, such applications include the main propulsion turbine, reduction gears and inboard shafting. Tin-based babbitt has long been the bearing sur
6、face material of choice in such applications because it combines good corrosion resistance, tolerance of misalignment and oil retention properties with the ability to heal over minor defects and to embed small dirt particles. Machining of bearing lands and surface finishing of babbitted surfaces are
7、 also compara- tively easy. 2. This standard provides the procedures that are to be foilowed,for prepara- tion and tinning of the shell surfaces before babbitting, for casting the babbitt and for quenching parts and finishing the surfaces after babbitting. .- iii Provided by IHSNot for ResaleNo repr
8、oduction or networking permitted without license from IHS-,-,-Paragraph 1 . 1.1 CONTENTS Page SCOPE . 1 Scope 1 2. REFERENCED DOCUMENTS 1 2.1 Government documents . 1 2.1.1 Specifications and standards . 1 2.2 Order of precedence 3 . 3.1 DEFINITIONS . 1 Free spread 1 4 . GENERAL REQUIRENENTS 1 4.1 G
9、eneral 1 4.2 Manufacturing and quality control procedures . 2 4.3 Manufacturing methods . 2 4.4 Quality control 2 5. DETAILED REQUIREMENTS . 2 5.1 Materials 2 5.1.1 Tinning 2 5.1.2 Babbitt 2 5.1.3 Fluxes . 2 5.1.4 Cleaning and etching agents 2 5.1.5 Shell materials 2 5.1.6 Asbestos . 2 5.2 Shell pre
10、paration 2 5.2.1 Shells for rebabbitting or babbitting 2 5.2.2 Shell machining 3 5.2.3 Babbitt-shell interface machining 3 5.3 Shell cleaning . 3 5.3.1 Mild and silver steels, copper and wrought iron 5.3.3 Nickel steel bearing shells 4 5.3.4 Tin bronze, phosphor bronze. brass and leaded 5.3.5 Cast i
11、ron bearing shells . 5 5.4 Shell stop-off . 5 5.5 Shell fluxing 6 5.5.1 Bath fluxing . 6 bearing shells 4 5.3.2 Medium carbon steel bearing shells . 4 brass bearing shells 4 5.3.6 Steel or bronze bearing shells . 5 5,5.2 Brush or spray fluxing . 6 5.6 Tinning 6 5.6.1 Flux removal . 7 5.6.2 Tinning c
12、ontrols . 7 5.7.1 Static babbitting process 7 5.7.1.2 Pouring for static babbitting 8 5.7.1.3 Quenching static cast babbitted shells . 8 5.7 Babbitting process . 7 iv Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,- DOD-STD-2188 33 m 7777733 0035859
13、3 m DOD-STD-2188(SH) 1 April 1987 CONTENTS . Continued Page Paragraph 5.7.2 Centrifugal casting process 8 5.7.2.1 Pouring for centrifugal babbitting . 9 5.7.2.2 Quenching centrifugally cast babbitted shells 9 5.8 Post-babbitting machining 9 5.8.1 Finished bearing . 10 5.10 Metrology equipment and fa
14、cilities . 10 5.10.1 Inspection system 10 5.9 Metallurgical bond test 10 . i 6 . NOTES . 10 6.1 Intended use . 10 6.2 Implementation guidance 10 6.3 Data requirements 10 6.4 Subject term (key word) listing 11 FIGURES Figure 1 Static casting jig 12 2 Cooling water arrangement . 13 a . v/vi Provided b
15、y IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-DOD-STD-2188(SB) 1 April 1987 1. SCOPE 1.1 Scope. This standard provides the requirements for static and centrifugal casting of QQ-T-390, grade 2 babbitt on steel or bronze bearing shells. 2. REFERENCED DOCUMENTS
16、 2.1 Government documents. 2.1.1 Specifications and standards. Unless otherwise specified, the following specifications and standards of the issue listed in that issue of the Department of Defense Index of-Specifications and Standards (DoDISS) specified in the solicitation form a part of this standa
17、rd to the extent specified herein. ?i SPECIFICATIONS FEDERAL QQ-T-371 - Tin, Pig. QQ-T-390 - Tin Alloy Ingots and Castings and Lead Alloy Ingots and Castings (Antifriction Metal) for Bearing Applications. STANDARDS MILITARY DOD-STD-2183 - Bond Testing, Babbitt Lined Bearings. MIL-STD-45662 - Calibra
18、tion Systems Requirements. (Copies of specifications and standards required by contractors in connec- tion with specific acquisition functions should be obtained from the contract- ing activity or as directed by the contracting officer.) 2.2 Order of precedence. In the event of a conflict between th
19、e text of this standard and the references cited herein, the text of this standard shall take precedence. 3. DEFINITIONS 3.1 Free spread. Free spread is the excess of the shell diameter measured in the plane of the parting line, over the shell diameter measured in the axial plane perpendicular to th
20、e plane of the parting line. 4. GENERAL REQUIREMENTS 4.1 General. All bearings ordered to be babbitted or rebabbitted in accordance with this standard shall meet the metallurgical bond test requirements specified in DOD-STD-2183 (see 5.9). Provided by IHSNot for ResaleNo reproduction or networking p
21、ermitted without license from IHS-,-,-DD-SlD-2188(SH) 1 April 1987 4.2 blanufacturing and quality control procedures. Manufacturing and quality control procedures shall produce babbitted or rebabbitted steel or bronze shell bearings with a ductile continuous bond between the babbitt and shell, and s
22、hell dimensions that will permit accurate installation in Naval machinery. 4.3 Manufacturing methods. Procedures shall be adaptable to static or centrifugal casting methods of tin-based babbitt. Shells may be new or rebab- bitted, as specified (see 6.2). Flame or plasma spraying shall not be used to
23、 babbitt or rebabbitt bearing shells or to repair bearing surfaces. 4.4 Quality control. Quality control procedures shall ensure that bond extent, strength and ductility meet the requirements of DOD-STD-2183. Quality control procedures shall ensure that bearing dimensions are within all require- men
24、ts of the manufacturing drawings. 5, DETAILED REQUIREPlENTS 5.1 Materials, 5.1.1 Tinning. Tinning processes shall employ commercially pure (99.75 percent) tin in accordance with QQ-T-371, grade A. 5.1.2 Babbitt Babbitt meeting the requirements of QQ-T-390, grade 2 shall be employed on all bearings m
25、anufactured to this standard. Babbitt shall not be contaminated with lead or other impurities beyond the limits specified in QQ-T-390 for grade 2 babbitt. 5.2.1 Shells for rebabbitting or babbitting. New shells may be fabri- cated from plate stock by rolling, or cut from thick-walled cylinders or ca
26、stings. Rebabbitting shall be limited to shells where the wall thickness is at least 12.5 millimeters (mm) (0.5 inch) and the finished babbitt thickness in the land regions of the babbitt is at least 1.6 mm (0.063 inch). Babbitting or rebabbitting of thin-wall precision inserts, such as for reciproc
27、ating engine bearings, is prohibited. Rebabbitting small bearings shall be performed only when it is cost-effective or when there is insufficient time to obtain new replacement bearings. 5.1.3 Fluxes. Ammonium chloride for fluxing tinning pot and zinc chlor- ide and ammonium chloride for fluxing she
28、lls shall be of commercial purity, conforming to the manufacturers technical grade or better. 5.1.4 Cleaning and etching agents. The chemicals used in any of the shell cleaning operations shall be of commercial purity, conforming to the manufacturer S technical grade, or better. 5.1.5 Shell material
29、s. The steel or bronze materials for the manufacture of new shells shall be as specified (see 6.2). 5.1.6 Asbestos. Under no conditions shall asbestos or products contain- ing asbestos be used to fulfill any of the requirements mentioned in this standard, 5,2 Shell preparation. 2 Provided by IHSNot
30、for ResaleNo reproduction or networking permitted without license from IHS-,-,-DOD-STD-2188iSH) 1 April 1987 O 5.2.2 Shell machining. New shells shall conform to the dimensions specified in the manufacturing drawings except that a free spread of up to 0.18 mm (0.007 inch) is permitted to compensate
31、for the closing in of the bearing that occurs when the babbitt is cast. The precise amount of free spread that should be present before babbitting depends on the shell material, babbitt thickness, pouring temperature and other factors. Generally this amount is determined empirically, and it may be i
32、ntroduced by plastic working of the shell after circular machining. Used shells considered for rebabbit- ting shall be inspected for major defects such as gross distortions, wear of the seating surface (or ball seat in bearings that have this alignment provi- sion) and large nicks, dents and holes.
33、Necessary repairs including plating, bring the shell into dimensional conformance with the manufacturing drawing. The original babbitt may be removed by melting out in a heated container or oven, or by machining. Free spread before rebabbitting shall be adjusted by plastic working of the shell to br
34、ing it to within the range permitted above for new shells. - welding, machining and stress relief shall be made before rebabbitting to * 5.2.3 Babbitt-shell interface machining. The surface of the shell to be babbitted on old and new bearings shall be finished with a single point high- speed tool bi
35、t to a surface finish of 130 roughness height rating or better, without the use of cutting fluid on the final cuts. Care shall be taken that the tool is sharp and that the babbitt shell interface is cut and free from the burnishing produced by worn cutting tool bits. Removal of original babbitt and
36、new interface machining may reduce thickness of used shells below the original manufacturers dimension. To be accepted for rebabbitting, the shell thickness, after interface machining, must be not less than the original manufacturers dimension by more than 1.6 mm (0.063 inch) or 10 percent of the or
37、iginal manufacturers dimension, whichever is smaller. 5.3 Shell cleaning. Shell cleaning is a critical step in preparing the shell for babbitting. High quality tinning will be achieved only if the surfaces are totally clean and free of contaminants. A high quality tin coating on the surfaces to be b
38、abbitted is essential for producing a continuous and high strength metallurgical bond between the babbitt and the shell. Various cleaning procedures may be used depending on the shell material and the processing steps that will be employed immediately before the tinning operation. Alternative cleani
39、ng procedures and the necessary steps in each case are described in 5.3.1 through 5.3.6. The method selected shall be based on the shell material, avail- able equipment, lot size, comparative costs and other such factors. Once the shells have been cleaned chemically, care shall be taken to prevent a
40、ny new contamination by oil or grease before tinning and subsequent babbitting. In all the cleaning procedures described in 5.3.1 through 5.3.6, the surfaces of the shell to be tinned and babbitted shall exhibit a clean matte finish after the final rinse. There shall be no breaks in the water surfac
41、e as the shell is drained. Any break in the water film is evidence of surface contamination. The cleaning process shall be repeated on any shell that exhibits such water breaks after final rinse. The chemicals used in the cleaning procedures are hazardous. 3 Provided by IHSNot for ResaleNo reproduct
42、ion or networking permitted without license from IHS-,-,-DOD-STD-2188(SH) 1 April 1987 5.3.1 Mild and silver steels, copper and wrought iron bearing shells. Oil and grease shall be removed by the following procedures and in the order shown : (a) Remove oil and grease from the shell surface either by
43、 vapor degreasing with chemicals such as trichloroethylene or by immersion in a boiling 4-1/2 percent lye solution (45 grams of lye per liter of water (6 ounces per gallon). (b) Rinse in boiling water. (c) Etch either by immersion in a 25 percent hydrochloric acid solution while the shell is still h
44、ot from the boiling water rinse, or by a 1-minute duration pickle in a boiling, 10-percent hydrochloric acid solution. (d) Final rinse in clean boiling water. 5.3.2 Eledium carbon steel bearing shells. Nedium carbon steel bearing shells shall be cleaned by the following procedure and in the order sh
45、own: (a) Clean the shell by immersion in a 60 percent nitric acid solution at room temperature until a uniform film of gas bubbles covers the shell (b) Rinse in clean boiling water. (c) Etch either by immersion in a 25 percent hydrochloric acid solution while the shell is still hot from the boiling
46、water rinse, or by a 1-minute duration pickle in a boiling, 10-percent hydrochloric acid solution. (d) Final rinse in clean boiling water. 5.3.3 Nickel steel bearing shells. Nickel steel bearing shells shall be prepared for tinning by anodic cleaning and etching. The shell shall be made anodic with
47、a current density of 110 to 330 amperes per square meter (10-30 amperes per square foot) of surface area at 6 to 12 volts direct current (dc), in a 30-percent sulfuric acid solution at 105 degrees Celcius (“C) (220 degrees Fahrenheit (F) for 3 minutes. All surfaces to be tinned shall have free acces
48、s to the acid solution and shall not be covered by clamps or electrical connections. After anodic cleaning and etching, the shell shall be final rinsed in clean boiling water. 5,3,4 Tin bronze, phosphor bronze, brass and leaded brass bearing shells. Bronze and brass bearing shells shall be cleaned b
49、y the following procedure and in the order shown: (a) Clean the shell by vapor degreasing with chemicals such as tri- chloroethylene, or by immersion in a boiling, 4-1/2 percent lye solution (45 grams of lye per liter of water (6 ounces per gallon). (b) Rinse in clean boiling water. (c) Etch in 60 percent nitric acid solution. (d) Dip in a 0.8 percent sodium cyanide solution (7.5 grams of sodium (e) Final rinse
