Class Vd2.I rj Book No. I 2-77 & NORTHEASTERN UNIVERSITY LIBRARY DAY DIVISION LIBRARY KULES This book may be kept 0.1?^.^ weeks. A fine of two cents will be charged for each day books or magazines arc kept overtime. Two books may be borrowed from the Library at one time. Any book injured or lost shall be paid for by the person to whom it is charged. No member shall transfer his right to use the Library to any other person. i FOUNDRY WORK FOUNDRY WORK A Text on Molding, Dry-sand Core-Making, and the Melting and Mixing of Metals R. E: WENDT Head Instructor in Foundry Practice, Purdue University ; Member of American Foundrymens Association and the Society for the Promotion of Engineering Education First Edition Third Impression McGRAW-HILL BOOK COMPANY, Inc. NEW YORK: 370 SEVENTH AVENUE LONDON: 6 & 8 BOUVERIE ST., E. C. 4 1923 TS Copyright, 1923, by the McGraw-Hill Book Company, Inc. PRINTED IN THE UNITED STATES OF AMERICA PREFACE In preparing this book, it has been the author's aim to provide a suitable text for schools and colleges and for use by apprentices in commercial shops. It is elementary to the extent that the student can grasp the fundamental principles of foundry work, yet deep enough to give a general working knowledge of foundry practice. The book consists of three parts. The first will enable the student to secure a general knowledge of foundry work, of the sizes and types of blast furnaces, and of the making of pig iron. The second provides instructions for practice in molding, coremaking and other parts of foundry work. The third part is devoted to the mixing and melting of metals. The material contained in this volume was obtained as a direct result of the author's experience in teaching apprentices in commercial shops and engineering students at Purdue University. The information on making coke, mining iron ore, operating blast furnaces, and chemical analysis of iron has been inserted to round out the volume and represents good commercial, practice. For many of the drawings the author is indebted to students taking foundry work under him, and for other illustrations to foundry supply firms. R. E. Wendt. W. Lafayette, Ixd. June, 1923. ^77S CONTENTS PAGE Preface v PART I FUNDAMENTAL PRINCIPLES CHAPTER I Foundry Cokes 1 Iron Ores—The Blast Furnace. CHAPTER II Commercial Foundry Layout 8 Foundry Product and Branches of Molding. CHAPTER III Molding Sand 13 Composition and Selecting of Sand, Tempering and Caring for Sand. CHAPTER IV Ramming the Sand 16 Venting the Mold—Facing for Molds—Parting Materials. CHAPTER V Flasks 21 Molding and Bottom Boards—Clamps and Weights. CHAPTER \T Gating Molds , 29 CHAPTER VH Shrinkage 34 Churning—Breaking Gates and Feeders from Castings. CHAPTER VIII Gaggers 41 Setting Cross Bars and Gaggers—Chaplets—Setting Chap- lets, Wedges. vii viii CONTENTS PAGE CHAPTER IX Tools 48 Questions on Part I 51 PART II EXERCISES AND PROBLEMS CHAPTER X Bench Molding and Molding Exercises 55 Exercises: No. 1, Face Plate; No. 2, Hexagonal Nut; No. 3, Ball Handle; No. 4, Oil Drip Cup; No. 5, Split Pattern of Collar; No. 6, Split Pulley; No. 7, Governor Pulley; No. 8, Sheave Wheel; No. 9, Bevel Gear Blank; No. 10, Embed- ding Face Plate; No. 11, Thinning a Plate; No. 12, Making Pulley Longer than Pattern. CHAPTER XI Floor Molding Exercises 82 Exercises: No. 13, Cone Pulley; No. 14, Flywheel; No. 15, Sugar Kettle; No. 16, Steam Engine Piston; No. 17, Lathe Bed; No. 18, Machine Base; No. 19, Lifting Dry-sand Core out of Pattern; No. 20, Open-sand Mold; No. 21, Sweep Molding—Pit Molding—Problems. CHAPTER XII Metal Patterns, Follow Boards, Match-Plates 120 CHAPTER XIII Molding Machines 127 CHAPTER XIV Dry-sand Core Making 132 Exercises: No. 1, Round Cores; No. 2, Cone Pulley Core; Plates—Ramming—^^enting Cores—Rodding Cores—Lifting Hooks—Pasting and Daubing Cores—Core Ovens and Bak- ing—Core Making Benches. CHAPTER XV Exercises in Dry Sand Core Making 142 Exercises: No. 1, Round Cores; No. 2, Cone Pulley Core; No. 3, Lathe Bed Core; No. 4, Machine Base Core; No. 5, Making Core with Pattern—Coremaking Machines. Questions on Part II 148 CONTENTS ix PART III MELTING AND MIXING METALS -^ — PAGE CHAPTER XVI Furnaces, General Construction of Cupola . Tuyeres, Cupola Linings and Lining the Cupola 153 General Construction of Cupola—Sizes of Cupolas—Tuy- eres—Cupola Linings—Lining the Cupola—Ladles—Blowers and Fans. CHAPTER XVn Preparing, Charging and Operating the Cupola 164 CHAPTER XVin Record Forms 174 CHAPTER XIX Foundry Irons 178 Mixing Irons by Fracture and Chemical Analysis—General Purpose Mixtures—Testing Gray Cast Iron. CHAPTER XX Non-ferrous Metal Founding 187 Alloying Non-ferrous Metals. Questions on Part III 195 Tables 197 Foundry Books for General Reading 198 Glossary of Foundry Terms 199 Index 203 PART I FUNDAMENTAL PRINCIPLES FOUNDRY WORK CHAPTER I FOUNDRY COKES There are two methods of manufacturing the coke used for melting metals. They are known as the Beehive-oven and By-product, or Retort, methods. The beehive method is the older and until recently the leading method. In the beehive process the air is admitted to the coking chamber for the purpose of burning all the volatile products of the coal. There is left a hard coke, silvery in appear- ance, good for melting metals. However, all the other products of the coal are wasted, and for that reason the beehive method is being replaced rapidly by the by-product method. In the manufacture of by-product coke, almost all of the useful ingredients in the coal are saved, yet the coke is of good quality for melting purposes. The by-product coke is darker than coke made by the beehive process and frequently is not so hard. When the two cokes are used for melting metals there seems to be very little difference between them. A beehive oven is shown in Fig 1, A indicating the fur- nace, B the charging level, C the receiving level, D the receiving door, E the charging hole, and F the car tracks. These ovens are built in sizes ranging from 10 to 12 ft. in diameter and from 6 to 8 ft. high. The inside of the oven is made of fire brick and the outside of stone. Bituminous coal is dumped into the oven from the top to a depth of about 2 ft. for 48-hr. coke or 21/2 ft. for 72-hr. coke. From 3 to 7 tons of coke are made every time the 3 4 FOUNDRY WORK oven is fired, the amount depending upon the size of the oven. After the impurities are burned off, the coke is drawn out and cooled with water. From 60 to 70 per cent of the coal charged is obtained as coke. The analysis of a good foundry coke should be as follows: Carbon from 88 to 92 per cent, ash from 6 to 10 per cent, and sulphur not over 1 per cent (as low as possible). Although beehive-oven and by-product cokes are almost always used for melting metals, both can be used for heat- ing purposes. /;^j^f^^^--^&^m\v Fig. 1. —Beehive coke oven. IRON ORES Iron ore is found in many parts of the United States. The largest iron-ore district is known as the Lake Superior district. The mines are scattered over the northern part of Michigan, Wisconsin, and Minnesota. About four-fifths of the iron mined is obtained in this region, and the ores are known as northern ores. The district next in size is known as the Birmingham district. It is located in the southern part of the country, and its ores are called south- ern ores. There are many varieties of iron ore. The ores most frequently used are known as the red and brown hematites. FOUNDRY COKES 5 The red hematite ore is used more than the brown hematite or any other ore. Magnetite and carbonate are used, but very little in comparison with the red hematite. The ores generally used to make pigs for gray-iron castings contain from 50 to 70 per cent of iron. An ore that contains less than 30 per cent is seldom used. The pig iron that the founder uses generally contains from 92 to 96 per cent of metallic iron. THE BLAST FURNACE The blast furnace, shown in Fig. 2, is used to extract iron from the ore, and the iron thus produced, called pig iron, is run into forms known commercially as pigs. All the iron that is used commercially is first passed through such a furnace. The size of the furnace varies in diameter from 20 to 35 ft., and in height from 100 to 125 feet. Fire brick and fire clay are used as linings. The bricks are made of silica, carbon, ganister, coke, magnesia and asbestos. About 450 tons of fire brick and 60 tons of fire clay are required to line a furnace of the size shown in the illustration. Four brick masons and twelve helpers are needed for approxi- mately 30 days to do the work. A space from 4 to 5 in. wide, between the bricks and the shell, is filled with granu- lated furnace slag mixed with water. From 1 to 2 weeks' time is required for the lining to dry. It is claimed that the lining will last for about 5 years under continuous operation. After the furnace has run a short time, the lining becomes protected by a carbona- ceous concrete from 2 to 12 in.