DOCSLIB.ORG

United States Patent [19] [111 3,903,585 Kosteruk Et Al

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
United States Patent [19] [111 3,903,585 Kosteruk Et Al United States Patent [19] [111 3,903,585 Kosteruk et al. [45] Sept. 9, 1975 [54] METHOD OF BRAZING 2.9791313 4/l96l Steinberg ....................... .. 29/504 X [761 ‘""emors: vakmi" pe‘mvkh Kosm'uki “msa 520918063 44 [3119231 19 gdulerifeurreta] e . .al. ........v . e . ...t 23:28: i M- Krlvonosa, 19» kv- 5;_Mikhail 3,442,006 5/l969 Grucket et a1...‘ 29/4711 x Savvich Kovalchenko. ulltsa 3,594,895 7/1971 Hill ....................... .. 29/504 x Kapitanovskaya, l0, kv. 20, both of 3,736,648 6/1973 Spielberg ......................... t. 29/4731 Kiev, U.S.S.R. [22] Filed: Ann 27, 1972 Primary Examiner—Francis S. Husar Assistant Examiner—Ronald J. Shore [2]] APPL N03 248,295 Attorney, Agent, or Firm—Waters, Schwartz & Nissen Related U.S. Application Data [63] Continuation of Ser. No. 875,503, Nov. l0, i969, [57] ABSTRACT abandoned‘ lnfusible metal alloys are employed both as a parts I ‘ material and as a brazing spelter for the connection of [52] U.S. Cl. ...... .... .. 75/134 V, 2222880122623, various parts and componems made of materialsrbascd [5 H I ‘ C‘ ‘ 823k suoz upon infusible metals and compounds, ceramics. [58 F’: ‘Id """" 473 1 graphite and the like. The alloys are based upon haf ] e o arc "" " ' ‘29/4729’ 477i 7’ nium to which is added some elements selected from ‘ ' ' the subgroup B of the ?rst group of the periodic sys tem and some elements featuring melting points lying [56] References Cited above 600°C and selected from the third to eighth UNITED STATES PATENTS groups of the periodic system. 2,739,375 3/l956 Coxe ............................ .t 29/473.l X 2,857,663 |0/19ss Beggs .............................. .. 29/504 x 5 Clainw N0 Drawings 3,903,585 1 2 METHOD OF BRAZING nitride, silicon nitride, silicon carbide and many others, This application is a continuation application of ap are not solderable with the use of available conven plication Ser. No. 875,503, ?led Nov. 10, i969 now tional brazing spelters. abandoned. Even in cases where the brazing of high-melting ma The present invention relates to infusible metal alloys terials is rendered practicable, e.g. when connecting employed as a material for various parts and compo graphite with high-melting metals by using a spelter nents and as a brazing spelter to connect various parts with a melting point between lOOO° to l500°C, each made of materials based on high-melting metals and particular brazing spelter possesses its own melting metal alloys, ceramics, graphite and the like. point which is a strictly ?xed constant value. Thus, Use of the herein-disclosed alloy as a brazing spelter brazing of graphite proceeds at a temperature of from may be made in chemical and electrochemical indus l200° to l300°C, each of the spelters being applicable tries for the connection of parts designed to operate in for only a certain range of materials. For instance, a zir corrodents; in electricsal~engineering, nuclear, aircraft conium-based spelter is applicable to the brazing of a and process industries for reinforcing critical and de?nite pair of materials, say, zirconium and poorly heavy-wear components parts and elements. fusible glass. Known inthe present state of the art are brazing al Additionally, a majority of hitherto-known brazing loys containing mostly silver and copper, bronze, plati compounds have a melting point lying not above lOOO° num and employed for soldereing or brazing such wide to l300°C, this being due to these incorporating rela ly-used construction materials, mostly metallic, as vari— tively low-melting substances. On this account, the ous grades of steel and metal alloys. 20 pressure of the vapors of some brazing compounds at However, gaining an ever-growing application at highly elevated temperatures (of the order of lOOO°C) present are materials based upon high melting-point ranges within ID’3 to H)‘4 mm Hg. Therefore, the ap compounds such as carbides, borides, nitrides and sili plication of the above-mentioned brazing spelters to cides, possessing special physico-chemical properties. high-vacuum engineering sometimes proves to be im From these materials are usually made critical parts of 25 practicable. ' various machines designed to operate under heavy con It is an object of the present invention to eliminate ditions such as blades of gas turbines therefore a neces the disadvantages discussed above. sity arises for such parts to be mechanically fastened to It is another object of the present invention to pro other parts made from conventional structural materi vide an alloy that is applicable as a material for making als, i.e., from various grades of steel and metal alloys. 30 various parts and components and as a brazing com Additionally, the above reason necessitates the provi pound for connecting various parts and components, sion of both electrical and thermal contacts between which alloy is capable of connecting a wide variety of both types of parts mentioned above. diverse materials based upon infusible compounds both ln current use are a plurality of soldering or brazing with one another and with other infusible metals, ce spelters enabling a partial solving of that problem as far ramics, graphite and like materials and the various as parts made of graphite, titanium, zirconium, tung physico-chemical properties of which can be regulated sten, niobium and their alloys are concerned. Thus, to insure the best working capacity of the material of when soldering thorium~tungsten wire to molybdenum the brazed connection under given conditions. parts in manufacturing cathode-ray tubes, use is made Said object is accomplished due to the face that the of platinum and its alloys with silver and gold as a braz 40 herein-disclosed alloy, according to the invention, is ing compound, the melting point of the latter falling be based upon hafnium to which is added some elements tween l400° and l8()0°C. selected from the subgroup B of the Ist group of the pe There are also known brazing compounds based riodic system within 2 and 30 percent of the total upon zirconium alloyed with vanadium, tungsten, tita weight of the alloy, said elements being taken either nium, beryllium and niobium additives, said com 45 separately or in various combinations with one another pounds being used for braze—jointing zirconium parts within the afore-stated weight percentage, and to which with poorly fusible glasses. the melting point of the is added also some elements selected from the lllrd to compounds lying between l050° and [300°C Vlllth groups of the periodic system, having a melting Palladium-based brazing spelters have a melting point lying above 600°C and taken either separately or point ranging between [000° and l500°C and are uti 50 in various combinations with one another within 2 to lized for braze-eonnection parts and components made 2l percent of the total weight of the alloy. of molybdenum, tungsten, zirconium and some heat The achieving of the above object has made it possi resistant alloys intended to operate under extra-high ble to provide an alloy that is in fact a highly versatile temperature conditions. brazing spelter capable of the connection of compo To provide a brazed-connection of graphite compo 55 nents made of the most diverse high-melting materials, nents with those made of titanium and zirconium and having a melting point regulatable within a wide tem their alloys, use is made currently of suspensions con perature range and possessing the most diverse physi stituted by ?nely comminuted powdery zirconium, tita co-chemical properties. nium, molybdenum or their alloys, and by gasoline~dis Hafnium, which is the base metal of the herein solved polystyrene. The speci?ed brazing conditions 60 proposed alloy, imparts a high adhesive property to the are as follows: melting point between l200° 'and latter with respect to infusible materials, as well as in l300°C, rarefaction l()"‘ to l0“5 mm Hg. To obtain sures a high melting point. high-quality brazed connections of graphitic compo Additives of the elements of the subgroup B of the lst nents with those made of molybdenum, zirconium, tita group of the periodic system taken in a quantity of from nium and niobium. use is made of brazing spelters con 65 2 to 30 weight percent contribute to the regulation of taining Au, Ni, Ti and Mo. the melting point of the herein-disclosed alloy within However, many of the materials based upon high the required limits, whereas some additives of the ele melting compounds such as boron carbonitride, boron ments selected from the lllrd to Vlllth groups of the pe~ 3,903,585 3 4 riodic system taken in an amount of from 2 to 21 rately or in various combinations with one another weight percent are instrumental in regulating the physi~ within the above-speci?ed limits, and some elements co-chemical properties of the alloy concerned herein. having a melting point lying above 600°C and selected To provide the regulation of the melting point of the from the third to eighth groups of the periodic system alloy within the temperature range of from 1000D to 5 within the range of from 2 to 2l percent of the total l200°C, it is advisable that the elements of the sub weight of the alloy, taken either separately or in various group B of the lst group of the periodic system be taken combinations within the afore-stated limits. in an amount of from 20 to 30 percent of the total The element of hafnium, a basal constituent of the weight of the alloy, while the regulation of the melting present alloy, is a chemically active metal thus contrib point of the alloy within the range of from l200° to 10 uting to high adhesivity of the alloy with respect to in 1500°C is attainable by taking the elements of the sub fusible materials, its high melting temperature calling group B of the lst group of the periodic system in a forth the high melting point of the alloy proper.
Load more

Recommended publications
  • Thesis-1959-M936z.Pdf (5.165Mb)
    THE ZING SMETIL'ING INDUSTRY IN OKLAHOMA By ROLAND DELOY MOWER ti Bachelor of Science University of Utah Salt Lake City, Utah 1955 Submitted to the Faculty of the Graduate Sohool of the Oklahoma State University in Partial Fulfillment of the Requirements for the Degree or MASTER OF SCIENCE August, 1959 STATE UNIVERSITY , LIBRARY . NOV 18 1959 1 ..'· TEE ZINC SMELTING mDUSTRY m OKLAHOMA Thesis Approved: tfa/r£~if:i:#d 7 Dean of the Graduate School 430809 ii PREFACE // ·one of the most mportant aspects of the tremendous development and growth of American industry is an increased awareness of the basic metals, their products and their uses o Steel, aluminum and copper are pa.rticu= larly well knO'wn because of the publicity they receive and because their presence is easily recognized in a wide range of consumer products. On the other hand zinc~ which ranks fourth among other metals with respect to production, is relatively unknown. Because zinc is generally used in conjunction with other metals its identity is often hidden and the average person, unaware of zinc's wide application and uses in industry, fails to reeog:nize its significan9e ,/ In this study of Oklahoma vs zinc smelting industry I have attempted to acquaint the average Oklahoman with zinc 1 its sources, products and consumers. The zinc industry as a whole is discussed.,- bttt special emphasis is given to that part of the industry located in Oklahoma. Information contained_ in this thesis was obtained from various published materials found in several libraries :i through personal
    [Show full text]
  • The Bristol Brass Industry: Furnace Structures and Their Associated Remains Joan M Day
    The Bristol brass industry: Furnace structures and their associated remains Joan M Day Remains of the once-extensive Bristol brass industry failed appear to have been complex. Political and can still be seen at several sites on the banks of the economic developments of the time contributed to A von and its tri butaries between Bath and Bristol.! varying extents. So too, did the availability of raw They are relics of the production of brass and its materials and good sources of fuel and waterpower, but manufacture which nourished during the eighteenth technical innovation in the smelting of copper, which century to become the most important industry of its was being evolved locally, provided a major component kind in Europe, superseding continental centres of of the initial success.3 It laid foundations for Bristol's similar production. By the close of the century Bristol domination of the industry throughout the greater part itself was challenged by strong competition and the of the eighteenth century. adoption of new techniques in Birmingham, and thereafter suffered a slow decline. Still using its Significantly, it was Abraham Oarby who was eighteenth-century water-powered methods the Bristol responsible as 'active man', together with Quaker industry just managed to survive into the twentieth partners, for launching the Bristol company in 1702. century, finally closing in the 1920s.2 After some five years' experience in employing coal• fired techniques in the non-ferrous metals industry he The factors which gave impetus to the growth
    [Show full text]
  • Samuel Wetherill, Joseph Wharton, and the Founding of the ^American Zinc Industry
    Samuel Wetherill, Joseph Wharton, and the Founding of the ^American Zinc Industry HE TWO people most closely associated with the founding of the zinc industry in the United States were the Philadel- Tphians Samuel Wetherill (i821-1890) and Joseph Wharton (1826-1909). From 1853 to about i860 they variously cooperated and competed with each other in setting up commercially successful plants for making zinc oxide and metallic zinc for the Pennsylvania and Lehigh Zinc Company at South Bethlehem, Pennsylvania. Both did their work in the face of an established and successful zinc industry in Europe. Accordingly, they looked to Europe for standards governing efficiency of production, quality of product, and the arts of management and marketing. They had to surpass at least some of these standards in order to establish the domestic industry on a firm basis. Zinc is a blue to grey metal found in deposits throughout the world. It is used for thousands of products, for example, in the fields of medicine, cosmetics, die casting alloys, galvanizing of iron, paint, rubber, ceramics, plastics, chemicals, and heavy metals. It ranks "only behind aluminum and copper in order of consumption among the nonferrous metals."1 In short, it has from an early stage in the Industrial Revolution been essential to the maintenance and progress of a technological society. The industry has two main branches. One is the manufacture of zinc oxide. The other is the making of metallic zinc or spelter, as it is called in the trade. These industries are relatively new in the western world. Portuguese and Dutch traders brought spelter to Europe from the Orient about the seventeenth century.
    [Show full text]
  • II/IV B. Tech (Regular) DEGREE Examinationapril'2018
    II/IV B. Tech (Regular) DEGREE EXAMINATIONApril’2018 Mechanical Engineering Casting, Forming and Welding Technology (14 ME 405) Detailed Scheme of Evaluation Max. Marks: 60 -------------------------------------------------------------------------------------------------------------------------------------- 1. Answer all the questions. (2x6=12) (a) Mention any two disadvantages of die casting Answer: 1) All metals and alloys cannot be cast. 2) The cost of machines, dies and other equipment used is high. 3) Not economical for small quantity production. 4) Heavy casting cannot be cast. 5) Special precautions are necessary for evacuation of air from die cavity, otherwise cause porosity. (b) What are the materials that are generally used for preparing patterns? Answer: Patterns may be constructed from the following materials. Each material has its own advantages, limitations, and field of application. Some materials used for making patterns are: wood, metals and alloys, plastic, plaster of Paris, plastic and rubbers, wax, and resins (c) Define the casting yield. Answer: The efficiency, or yield, of a casting is defined as the weight of the casting divided by the weight of the total amount of metal poured (d) What is the most commonly used type of gate? Answer: Horizontal Gating System is used most widely. (e) Specify the advantages of the precision investment casting process. Answer: -Excellent surface finish -High dimensional accuracy -Extremely intricate parts are castable -Almost any metal can be cast -No flash or parting lines (f) How is a semi-permanent mould different from a permanent mould? Answer: In a permanent mold casting there are two molds used and these molds are joined together in which metals are molted when poured in these molds.
    [Show full text]
  • Zinc Transfer from China to Europe Via Trade, Ca. 1600–1800 a Transnational Perspective
    Zinc Transfer from China to Europe via Trade Zinc Transfer from China to Europe via Trade, ca. 1600–1800 A Transnational Perspective BY CHEN HAILIAN Abstract Previous studies of zinc in China and Europe have largely concentrated on issues of the origin of zinc in a specifi c place but have not addressed the connections and relationships produced and used between China and Europe because of zinc. This paper is the fi rst attempt to approach the history of zinc transfer from China to Europe from a transnational perspective. 1 My narra- tive of this zinc transfer goes beyond a classical comparison of two trading patterns modelled on the major factors of transfer. Instead, by viewing trade as a vehicle for moving commodities and transmitting ideas, knowledge and technology, I interpret the transfer of zinc from China to Europe chronologi- cally on two levels: both the physical movement or fl ow of zinc as an object or commodity that was being incorporated into producing a series of new goods, especially in such as imitating golden decorations; and the technology for producing the metal. In order to examine both aspects, I discuss Chinese zinc and European inventions within their larger technological, economic, political, social and cultural contexts and address the following questions: why did the large-scale use of zinc emerge in China? How did Chinese zinc arrive in Europe and how was zinc adopted as a new raw material? Why and how was zinc discovered and produced in Europe? As my fi ndings suggest, the arrival of Chinese zinc in Europe a ballast item led to its adoption in the production of new goods in Europe, for instance being used to produce imitation gold ornaments and toys.
    [Show full text]
  • “Spelter Chills.”
    370 RIESMAX, boles: SPELTER CIIILES “SPELTER CHILLS."1 By David Riesmax, M.D., ASD Russell S. Boles, M.D., I,HILADF.M,jnA. (From the Medical Division of the Philadelphia General Hospital.) In recent years the results obtained from the study of occupational diseases lias been most gratifying. Such a study not only often aids in arriving at an otherwise difficult diagnosis, but as a part of industrial hygiene it has become of great importance in the pre¬ vention of those ills that arc the result of occupation. With this in mind a systematic study of occupational diseases is being made in the medical division of the Philadelphia General Hos¬ pital, and the affection about to be described is one of a number of interesting conditions revealed by this study. “Spelter chills” is the name given to a condition heretofore but briefly described under such varying terms as brass-founders’ ague, brass chills, zinc chills, smelter shakes, das Giesfiebcr or Staubficbcr, and fitivre des fondeurs. We believe the condition results from the inhalation and ingestion of the fumes and flakes of zinc oxide arising from the melting and volatilizing of spelter, which is the commercial name for zinc in its impure state. Spelter chills wc found to be the name popularly employed among the local workmen. The chills occur in brass foundries, in zinc smelters, and in places where zinc is poured. The majority of instances are found in places where yellow brass is manufactured, a process in which a large percentage of zinc is used. The chills do not occur in those engaged in processes in which the zinc is not volatilized.
    [Show full text]
  • William Champion's Warmley Brass and Zinc Works Archaeological Investigations 1994 to 2011 Etheridge and Dungworth, Avon
    William Champion’s Warmley Brass and Zinc works, Warmley, South Gloucestershire. Archaeological Investigations and Recording 1994-2011 Illustration taken from the ‘Annales des Mines” Vol 10, dated 1825 by David James Etheridge with scientific analysis by Dr David Dungworth Avon Archaeological Unit Limited Avondale Business Centre, Woodland Way, Kingswood, Bristol, BS15 1AW Bristol 2012 William Champion’s Warmley Brass and Zinc works, Warmley, South Gloucestershire. Archaeological Investigations and Recording 1994-2011 William Champion’s Warmley Brass and Zinc works: Archaeological Investigations and Recording 1994-2011 William Champion’s Warmley brassworks, founded c. 1746, was the first integrated brass manufacturing site, where all parts of the operation, from raw material processing to the finished product, were undertaken at one location. A review of archaeological interventions and recording undertaken between 1986 and 2011, together with a new scientific analysis of the technological residues, shows that despite development of the site over the last 160 years, substantial structural remains and industrial waste deposits related to the 18th century works are preserved below ground. In particular, the remains of Britain’s oldest surviving industrial zinc smelter have now been identified. I INTRODUCTION The civil parish of Warmley is located towards the western edge of the Bristol conurbation, some 8km from the city centre, within the unitary authority of South Gloucestershire, formerly within the non-metropolitan district of Kingswood in the County of Avon. The parish, formerly rural, is largely suburban, with some light industry and retail. The site (Fig. 1), centred on NGR ST 66950 72870, lies at the junction of Tower Lane with Tower Road North, on a westerly projecting spur of land between 35 and 50m aOD.
    [Show full text]
  • Bearings and Bearing Metals
    BEARINGS AND BEARING METALS BY WILLIAM VAN DUNKIN B. S. University of Illinois, 1903 THESIS Submitted in Partial Fulfillment of the Requirements for the Degree of MECHANICAL ENGINEER IN THE GRADUATE SCHOOL OF THE UNIVERSITY OF ILLINOIS 1909 UNIVERSITY OF ILLINOIS THE GRADUATE SCHOOL Way 1909 I HEREBY RECOMMEND THAT THE THESIS PREPARED UNDER MY SUPERVISION BY WILLIAI;; VAN DUNKIIT, B.S., 1903 ENTITLED BEARINGS AKD BEARING METALS BE ACCEPTED AS FULFILLING THIS PART OF THE REQUIREMENTS FOR THE DEGREE OF MECHANICAL ENGINEER In Charge of Major Work ead of Department Recommendation concurred in: Committee Cl4(yrajZ^ on Final Examination 145021 o BEARIiIGS A H D BEARIHG METALS Digitized by the Internet Archive in 2013 http://archive.org/details/bearingsbearingmOOvand COITTEITTS. PART I. Introduction Page Bearings Friction 1 Unlubricated Surfaces £ Lubricated Surfaces 2 Frictional Resistances Due to Viscositj?- , 2 Friction of Oily Surfaces in Contact. 5 Film Friction 6 Intermediate Friction 9 Coefficient of Friction The Influence of the Lubricant 10 The Point of Delivery of the Oil 1£ The Influence of the Speed 13 The Influence of the Bearing Pressure . 13 The Influence of the Temperature 15. The Effect of the Material Forming the Journals 16 The Influence of the Clearance "between Journal ^nd Bearing 17 Formula 18 Design of a Bearing 21 PART II. Bearing Metals The Microstructure of Bearing Metals 27 The Microscope 27 ii The Preparation of the Sample 28 Methods of Examination 28 Points to he Considered in Selecting Bearing Metals Resistance to Crushing 32 Elastic Tension 32 Tensile Strength 32 Resistance to Heating 34 Anti-Friction 34 Relation between Composition and Wear 35 Alloys Suitable for Journal Bearings 38 Composition and Structure of Alloys Used for Bear- ings 39 Testing of Bearing Metals 49 Bearing Metals for Automobile Work 52 Alloys for Rail Road Bearings 60 Subjects Suggested for Further Investigation and Study .
    [Show full text]
  • Wire Rope Terminations
    WIRE ROPE TERMINATIONS Warnings and Application Instructions For U-Bolt Clips Efficiency ratings for wire rope end terminations are based upon the catalog breaking strength of wire rope. The effi- ciency rating of a properly prepared loop or thimble-eye termination for clip sizes 1/8˝ through 7/8˝ is 80%, and for sizes 1˝ through 3-1/2˝ is 90%. Figure 5 The number of clips shown (see Table 1) is based upon using RRL or RLL wire rope, 6 x 19 or 6 x 37 Class, FC or IWRC; IPS or XIP. If Seale construction or similar large outer wire type construction in the 6 x 19 Class is to be used for sizes 1˝ and larger, add one additional clip. If a pulley (sheave) is used for turning back the wire rope, add Figure 6 one additional clip. The number of clips shown also applies to rotation- 5. WIRE ROPE SPLICING PROCEDURES: resistant RRL wire rope, 8 x 19 Class, IPS, XIP, sizes The preferred method of splicing two wire ropes together 1-1/2˝ and smaller; and to rotation-resistant RRL wire is to use interlocking turnback eyes with thimbles, using rope, 19 x 7 Class, IPS, XIP, sizes 1-3/4 inch and smaller. the recommended number of clips on each eye (See Figure For other classes of wire rope not mentioned above, 5). 4 we recommend contacting Crosby Engineering at the An alternate method is to use twice the number of clips as address or telephone number on the back cover to ensure used for a turnback termination.
    [Show full text]
  • American Zinc, Lead and Smelting Company Records, 1901-1965
    R American Zinc, Lead and Smelting Company. 010 Records, 1901-1965. 154 boxes. NOTE: THIS COLLECTION IS IN OFF-CAMPUS STORAGE. AT LEAST TWO DAYS' ADVANCE NOTICE IS REQUIRED FOR RESEARCH USE. This collection is available at The State Historical Society of Missouri. If you would like more information, please contact us at [email protected]. The American, Lead and Smelting Company (commonly known as “American Zinc”) was a large nonferrous metals firm which mined, processed, smelted, and marketed basic zinc and lead products. It had major mining and milling operations in Missouri, Wisconsin, and Tennessee, smelters in Kansas and Illinois, and interests in ore processing machinery. Founded in 1899, the company became a leader in the zinc industry. By 1965 it controlled the largest zinc ore reserves in the United States, and ranked second in zinc ore production and third in smelting capacity. By that time controlling interest in the firm had passed to Consolidated Gold Fields, Ltd., a mining in- vestment company. James D. Norris’s AZn: A History of the American Zinc Company (Madison: State Historical Society of Wisconsin, 1968), based in large part upon this collection, is an excellent general history of the firm. These records, secured from the company's administrative offices in St. Louis, have been organized into three major sections: An inventory for each section follows below. Section 1:-- Harry S. Kimball File, 1901-1930 (15 boxes) Section 2-- Walter G. Swart File, ca. 1907-1915 (12 boxes) Section 3-- Howard I. Young File, ca. 1925-1965 (127 boxes) r106 14 January 1982 WHMC-St.
    [Show full text]
  • Hard Soldering
    Welding Module 19.2.1 Hard Soldering • Hard soldering is a general term for silver soldering and brazing . • These are very similar thermal joining processes to soft soldering in as much that the parent metal does not become fused or molten and that the filler alloy has to have a lower melting temperature range than the metals being joined. Module 19.2.1 Explain the basic principles of hard soldering and braze welding. Principles: joint types and materials joined, solders, fluxes, heating equipment, applications, safety precautions Hard Soldering • The term ‘ brazing ’ is derived from the fact that the filler material (spelter) is a brass alloy of copper and zinc and a typical spelter containing 40% copper and 60% zinc melts at about 850°C to produce a strong and malleable joint. This is very much higher than the temperatures required when soft-soldering. • Brazing is defined as a process of joining metals in which the molten filler material is drawn into the gap between the closely adjacent surfaces of the metals being joined by capillary attraction. Principles of Brazing • The selection of a suitable filler alloy which has a melting range that is appreciably lower than that of the parent metals being joined – but substantially higher than that used for soft soldering. • The thorough cleanliness of the surfaces being joined. Previously soft-soldered joints cannot be remade by hard soldering. • The complete removal of the oxide film from the surfaces of the parent metal and the filler material by a suitable flux. • The complete ‘ wetting ’ of the joint surfaces by the molten brazing alloy.
    [Show full text]
  • TOXICOLOGICAL REVIEW of ZINC and COMPOUNDS (CAS No
    EPA/635/R-05/002 TOXICOLOGICAL REVIEW OF ZINC AND COMPOUNDS (CAS No. 7440-66-6) In Support of Summary Information on the Integrated Risk Information System (IRIS) July 2005 U.S. Environmental Protection Agency Washington D.C. DISCLAIMER This document has been reviewed in accordance with U.S. Environmental Protection Agency policy and approved for publication. Mention of trade names or commercial products does not constitute endorsement or recommendation for use. ii CONTENTS —TOXICOLOGICAL REVIEW OF ZINC AND COMPOUNDS (CAS No. 7440-66-6) LIST OF TABLES .............................................................v FOREWORD ................................................................ vi AUTHORS, CONTRIBUTORS, AND REVIEWERS ............................... vii 1. INTRODUCTION ..........................................................1 2. CHEMICAL AND PHYSICAL INFORMATION RELEVANT TO ASSESSMENTS ....3 3. TOXICOKINETICS RELEVANT TO ASSESSMENTS ............................6 3.1. ABSORPTION ........................................................6 3.1.1. Gastrointestinal Absorption .........................................6 3.1.2. Respiratory Tract Absorption ........................................8 3.2. DISTRIBUTION .......................................................8 3.3. METABOLISM .......................................................9 3.4. ELIMINATION AND EXCRETION .......................................9 3.5. PHYSIOLOGICALLY-BASED TOXICOKINETIC MODELS .................10 4. HAZARD IDENTIFICATION ...............................................11
    [Show full text]