[PDF] Introduction to Physical Metallurgy (1974).pdf

View - Download Introduction to Physical Metallurgy (1974).pdf

Previous PDF

Next PDF

INTRODUCTION TO PHYSICAL METALLURGY

Second Edition

SIDNEY

H. AVNER

Professor

New York City Community College

City University of New York

McGRAW-HILL BOOK COMPANY

Auckland Bogots Guatemala Hamburg Lisbon

London Madrid Mexico New Delhi Panama Paris San Juan

SHo Paulo Singapore Sydney Tokyo

INTRODUCTION TO PHYSICAL METALLURGY

INTERNATIONAL EDITION

Copyright @ 1974

Exclusive rights by McGraw-Hill Book Co

- Singapore for manufacture and export. This book cannot be re-exported from the country to which it is consigned by

McGraw-Hill.

Copyright

@ 1974, 1964 by McGraw-Hill, Inc. All rights reserved. No part of this publication may be reproduced or distributed in any form or by any means, or stored in a data base or retrieval system, without the prior written permission of the publisher. Library of Congress Cataloging in Publication Data

Avner, Sidney H

Introduction to physical metallurgy.

Includes bibliographies.

1. Physical metallurgy. I. Title.

&A86 1974 669'.9 74-807

1 0-07-002499-5

ten ordering this title use ISBN 0-07-Y85018-6

CONTENTS

Preface

Introduction

1. Tools of the Metallurgist

2. Metal Structure and Crystallization

3. Plastic Deformation

4. Annealing and Hot Working

5. Constitution of Alloys

6. Phase Diagrams

7. The Iron-Iron Carbide Equilibrium Diagram

8. The Heat Treatment of Steel

9. Alloy Steels

10. Tool Steels

11. Cast Iron

12. Nonferrous Metals and Alloys

13. Metals at High and Low Temperatures

14. Wear of Metals

15. Corrosion of Metals

16. Powder Metallurgy

17. Failure Analysis

Appendix: Temperature-conversion Table

Glossary

Index v

vii 1 65
107
129
147
155
225,
249
349
387
423
461
547
567
583
605
633
inted in Singapore

PREFACE

Kenny, and Jeffrey,

in whose hands the future lies The emphasis of the second edition of this text remains on the basic con- cepts and applications of physical metallurgy. The level of this edition is also essentially unchanged. The text is still considered appropriate for the teaching of physical metallurgy to students who are not majors in metallurgy as well as to engineering students as an introductory course. It has also proved useful for technician training pro- grams in industry. The fundamental concepts are still presented in a sim- plified form yet as accurately as possible. The only background required is an elementary course in physics. During the past decade, the first edition of this text was found to be quite effective, and many favorable comments were received from both students and faculty members. However, advances in certain areas and suggestions from users have necessitated a revision of the first edition. The following is a summary of the most notable improvements in the second edition:

In Chapter

1, which covers some of the important tools and tests in the

field of metallurgy, the section on nondestructive testing has been ex- panded to include eddy current testing and holography. The latest ASTM code has been used in the section on hardness testing.

Some changes have been made in Chapter

2 in order to make the simpli-

fied explanation of atomic and metal structure more understandable. A brief explanation of x-ray diffraction and grain size measurement was added.

Chapters

3 and 4 which cover the fundamentals of plastic deformation

and the effect of heat on cold-worked materials remain essentially the same except for an expanded discussion of dislocations and fracture.

Chapter

6, on binary phase diagrams, now includes diffusion, a more

detailed explanation of the theory of age hardening, and more actual phase diagrams as illustrations.

Chapter

7 which considers the iron-iron carbide equilibrium diagram in

some detail now also discusses wrought iron and the effect of small quantities of other elements on the properties of steel.

The section on case hardening of steel in Chapter

8 has been expanded

to include a more detailed explanation of nitriding, flame hardening and induction hardening. A section on hardenable carbon steels has also been added.

In Chapter

9, the portion on stainless steels now encompasses new

sections on precipitation-hardening stainless steels, maraging steels, and ausforming.

In Chapter

10 the section on cemented carbide tools has been expanded

and a new section on ceramic tools has been added.

Chapter

11 now covers only cast iron and has been enhanced by addi-

tional diagrams. The numerous additional photomicrographs added to Chapter 72 il- lustrate various nonferrous microstructures. An entire section on titanium and titanium alloys has been included because of their increased com- mercial importance. The chapter on wear of metals has been moved next to the one on cor- rosion of metals to improve the continuity of subject matter.

Chapter

15 now discusses the corrosion of metals in greater detail.

A brief discussion of the powder metallurgy processing techniques has been added to Chapter 16. There are two major changes in this edition as compared to the first edition.

1. The replacement of Chapter 17 on extractive metallurgy by an entirely new chap-

ter on failure analysis. It was felt that extractive metallurgy was not really part of physical metallurgy and that a chapter on failure analysis would be of greater in- terest and value to technicians and engineers.

2. The addition of a glossary of terms related to physical metallurgy.

There IS very little on the details of operation of heat-treating and testing equipment since they are covered in the laboratory course which is taken in conjunction with the theory course. Numerous photomicrographs have been used to illustrate typical struc- tures. Many tables have been included to present representative data on commercial alloys. The aid received from the following people in reading portions of the manuscript or in preparations of photomicrographs for the first edition is gratefully acknowledged:

J.E. Krauss, G. Cavaliere, A. Dimond, A. Smith,

A. Cendrowski,

J. Sadofsky, C. Pospisil, T. Ingraham. J. Kelch, and 0. Kammerer. Many companies have contributed generously from their pub- lications and credit is given where possible. I make no particular claim for originality of material. The information of other al~thors and industrial companies has been drawn upon. The only justification for this book, then, lies in the particular topics covered, their sequence, and the way in which they are presented. I would like to express my appreciation to Miss Barbara Worth for typing most of the first edition manuscript, to Mrs. Helen Braff and Mrs. Lillian Schwartz for typing the second edition material, and finally to my wife, without whose patience and understanding this book could never have been written.

Sidney

H. Avner Metallurgy is the science and technology of metals. It is beyond the scope of this text to cover the development of metallurgy as a science. Only certain highlights will be mentioned here for the purpose of orientation. The worker of metals is mentioned in the Bible and in Greek and Norse mythology. Metallurgy as an art has been practiced since ancient times. Ancient man knew and used many native metals. Gold was used for orna- ments, plates, and utensils as early as 3500

B.C. The art of smelting, refin-

ing, and shaping metals was highly developed by both the Egyptians and the Chinese. The ancient Egyptians knew how to separate iron from its ore and that steel had the ability to harden. but iron was not used widely before

1000 B.C. Iron was not popular with ancient people because of its

tendency to rust, and they preferred working with gold, silver, copper, brass, and bronze. Knowledge of dealing with metals was generally passed directly from master to apprentice in the Middle Ages, leading to an aura of super- stition surrounding many of the processes. Very little was written on metal- lurgical processes until Biringuccio published his "Pirotechnia" in 1540, followed by Agricola's "De Re Metallurgica" in

1556. In succeeding years,

much knowledge was added to the field by people trying to duplicate the composition and etched structure of Damascus steel. Until the beginning of the last quarter of the nineteenth century, most investigations of metal structure had been macroscopic (by eye) and super- ficial. The science of the structure of metals was almost nonexistent. The situation was ripe for the detailed attention of individuals whose back- ground was more scientific than practical. The individual most responsible for the period of rapid development that followed was Henry Clifton Sorby. Sorby was an amateur English scientist who started with a study of meteorites and then went on to study metals.

In September

1864, Sorby presented a paper to the British Association

for the Advancement of Science iil which he exhibited and described a number of microscopical photographs of various kinds of iron and steel. This paper marks the beginning of metallography, the field concerned with the use of the microscope to study the structure of metals. It seems that while many people appreciated the value of Sorby's studies at the time they were done, none of them had sufficient interest to develop the technique independently, and metallography lay dormant for almost twenty years. Additional work by Martens in Germany (1878) revived Sorby's interest in metallurgical problems, and in 1887 he presented a paper to the tron and Steel Institute which summarized all his work in the field. Considerable attention was now generated by both scientists and industrial metal- lurgists in other countries. In the early part of the twentieth century, Albert Sauveur convinced American steel companies that the microscope was a practical tool to aid in the manufacture and heat treatment of steel. About

1922, more knowledge of the structure and properties of metals

was added by the application of x-ray diffraction and wave mechanics. Metallurgy is really not an independent science since many of its funda- mental concepts are derived from physics, chemistry, and crystallography. The metallurgist has become increasingly important in modern tech- nology. Years ago, the great majority of steel parts were made of cheap low- carbon steel that would machine and fabricate easily. Heat treatment was reserved largely for tools. Designers were unable to account fcr structural inhomogeneity, surface defects. etc., and it was considered good practice to use large factors of safety. Consequently, machines were much heavier than they should have been, and the weight was considered a mark of quality. This attitude has persisted, to some extent, to the present time but has been discouraged under the leadership of the aircraft and automotive industries. They have emphasized the importance of the strength-weight ratio in good design, and this has led to the development of new high- strength, lightweight alloys. New technical applications and operating requirements pushed to higher levels have created a continued need for the development of new alloys. For example, an exciting development has been the Wankel rotary engine- an internal combustion engine of unusual design that is more compact, lighter, and mechanically far simpler than the ordinary reciprocating piston motor of equivalent horsepower.

A particularly bothersome problem has

been the seals between the rotor and the metal wall. Originally, the seals were made of carbon and seldom lasted more than 20,000 miles. Research developed a new sintered titanium-carbide alloy seal which has given life- times of up to 100,000 miles. The metallurgical field may be divided into two large groups:

1. Process or extractive metallurgy-the science of obta~ning metals from the~r

ores, includtng mining, concentration, extraction. and refining metals and alloys.

2. Physical metallurgy-the science concerned with the physical and mechanical

characteristics of metals and alloys. This field studies the properties of metals and alloys as affected by three variables: a. Chemical composition-the chemical constituents of the alloy b. Mechanical treatment-any operation that causes a change in shape such as rolling, draw~ng, stamping, forming, or machining c. Thermal or heat treatment-the effect of temperature and rate of heating and cool~ng

REFERENCES

Hoover and Hoover: "Georgius Agricola's De Re Metailurgica." Dover Publications,

New York, 1912.

b Howe, H. M.: The Metallurgy of Steel, The Engineering and Mining Journal, 1st ed.,

New York, 1890.

Rickard, Thomas': "Man and Metals," McGraw-Hill Book Company, New York, 1932. Sauveur, Albert: "The Metallography and Heat Treatment of Iron and Steel," 4th ed.,

McGraw-Hill Book Company, New York, 1935.

Smith and Gnudi: "Pirotechnia of Vannoccia Biringuccio," American Institute of Mining and Metallurgical Engineers, New York, 1943.

Smith, Cyril Stanley:

"A History of Metallography," University of Chicago Press, 1960.

Sullivan,

F.: "The Story of Metals," American Society for Metals, Metals Park. Ohio, viii 1951.

TOOLS OF THE

I METALLURGIST

The purpose of this chapter is to glve the student an understanding of some of the common tools and tests that are used in the metallurgical field.

1.1 Temperature Scales In scientific research and in most foreign countries,

the standard temperature-measuring scale is the centigrade scale. How- ever. in American industrial plants, the Fahrenheit scale is used almost exclusively. Therefore, all references to temperature in this book will be in terms of the Fahrenheit scale since this is the one most likely to be en- countered by the industrial technician. Conversion from one scale to the other may be made by the following equations: 'C = 5:9 - 32 (1.1) "F = 9:5 'C + 32 (1.2) The accuracy with which temperatures are measured and controlled will determine the successful operation of some metallurgical processes such as casting, smelting, refining, and heat treatment. It will also have a profound effect on the strength properties of many metals and alloys.

TEMPERATURE MEASUREMENT

In order to understand the effect of thermal treatment on the properties, it is necessary to have some knowledge of how temperature is measured. Pyrometry deals with the measurement of elevated temperatures, gen- erally above 950"F, 5nd instruments used for this purpose are known as pyrometers.

155 2. -

Thermometry deals with the measurement of temperatures below 950°F, and instruments for this purpose are known as thermometers. 1.2 Temperature Measurement by Color One of the simplest methods of esti; mating the temperature of a metal is by noting the color of the hot body. There is an apparent correlation between the temperature of a metal and

2 INTRODUCTION TO PHYSICAL METALLURGY

TABLE 1.1 Variation of Color

with Temperature

COLOR TEMP.. "F

TOOLS OF THE METALLURGIST 3

Farnt red

Dark red

Dark cherry

Cherry red

Bright cherry

Dark orange

Orange

Yellow

its color, as shown by Table 1.1. Except when applied by an experienced observer, this method will give only rough temperature estimates. The principal difficulty is that judgment of color varies with the individual. Other sources of error are that the color may not be uniform and may vary somewhat with different materials. If a continuous indication or recording of temperature is required, then the instruments in use may be divided into two general classifications: (1) mechanical systems that deal essentially with the expansion of a metal, a liquid, a gas or vapor; and (2) electrical systems which deal with resis- tance, thermocouple, radiation, and optical pyrometers.

1.3 Metal-expansion Thermometers Most metals expand when heated, and

the amount of expansion will depend upon the temperature and the co- efficient of expansion. This principle is incorporated in the bimetallic strip which is used in the common thermostat. The bimetallic strip is made by bonding a high-expansion metal on one side with a low-expansion metal on the other. As a result of small temperature changes, the strip will curve and therefore make or break an electrical circuit which will control the heating of a house. When it is used as an industrial temperature indicator, the bimetallic strip is usually bent into a coil, one end of which is fixed so that on expan- sion a rotary motion is automatically obtained (Fig. 1.1). Fig. 1.1 Industrial temperature indicator with a helm bimetallic element. (By permission from P.

J. O'Higgins.

"Basic Instrumentation," McGraw-Hill Book Company.

New York,

1966.)

covered c~~iilory \ Fig. 1.2 S~mple thermal system for industrial temperature measurement. (By permission from P.

J. O'Higgins, "Basic

Instrumentation." McGraw-Hill Book Company. New York.

I966.)

Most bimetallic strips have lnvar as one metal, because of its low coeffi- cient of expansion, and yellow brass as the other metal for low tempera- tures or a nickel alloy for higher temperatures. They can be used in the range of -100 to 1000"F, are very rugged, and require virtually no main- tenance, Their main disadvantage is that. owing to the necessity for enclos- ing the element in a protecting tube, the speed of response may be lower than that of other instruments.

1.4 Liquid-expansion Thermometers The remainder of the mechanical system

temperature-measuring instruments, whether liquid-expansion or gas- or vapor-pressure, consist of a bulb exposed to the temperature to be mea- sured and an expansible device, usually a Bourdon tube, operating an indicating pointer or a recording pen. The bulb and Bourdon tube are connected by capillary tubing and filled with a suitable medium (Fig. 1.2). The liquid-expansion thermometer has the entire system filled with a suitable organic liquid or mercury. Changes in bulb temperature cause the liquid to expand or contract, which in turn causes the Bourdon tube to expand or contract. Temperature changes along the capillary and at the case also cause some expansion and contraction of the liquid, and some form of compensation is therefore required. Figure

1.3 shows a fully com-

pensated.liquid-expansion thermometer using a duplicate system, less bulb, arranged so that motions are subtracted. Some of the liquids used and the temperatures covered by them are:

Mercury -35 to +950°F

Alcohol -110 to -160°F

Pentane +330 to

+ 85°F

Creosote +20 to +400°F

1-5 Gas- or Vapor-pressure Thermometers In the vapor-pressure thermometer,

a volatile liquid partially fills the bulb. Different temperatures of the bulb cause corresponding pressure variations in the saturated vapor above the tiquid surface in the bulb. These pressure variations are transmitted to the

4 INTRODUCTION TO PHYSICAL METALLURGY

TOOLS OF THE METALLURGIST 5

Auxiliary

quotesdbs_dbs8.pdfusesText_14

[PDF] powder metallurgy journal pdf

[PDF] powder metallurgy methods and applications

[PDF] powder metallurgy pdf nptel

[PDF] powder metallurgy ppt

[PDF] powder metallurgy process

[PDF] powder metallurgy science randall m german pdf

[PDF] powder processing

[PDF] powder production methods pdf

[PDF] power and solidarity definition

[PDF] power and solidarity tannen

[PDF] power bottom emoji

[PDF] power chords chart pdf

[PDF] power distance

[PDF] power frequency 50hz or 60hz

[PDF] power frequency 50hz or 60hz camera