STAINLESS STEEL,
SOLDERING AND
WELDING
www.indiandentalacademy.com
INDIAN DENTAL ACADEMY
Leader in continuing dental educa...
STRUCTURE OF MATTER
 Study of dental materials and its
properties particularily of solids.
 Basic materials used in the ...
INTER ATOMIC BONDS
 PRIMARY BONDS
Ionic bonds Covalent bonds
Metallic bonds
www.indiandentalacademy.com
 SECONDARY BONDS
(Vander waals force)
www.indiandentalacademy.com
EQUILIBRIUM INTER ATOMIC
DISTANCE
 Limiting factor for the atoms & molecules
from approaching each other too closely.
 B...
 Forces of
attraction versus
forces of repulsion
dictating the
equilibrium
position of the
atoms.
www.indiandentalacademy...
CRYSTAL STRUCTURE
 UnitCell-smallest
repeating unit that is
contained in a crystal.
 SpaceLattice-any
arrangement of ato...
BCC FCC HCP
www.indiandentalacademy.com
CRYSTAL IMPERFECTIONS
 Point defects
Impurities
vacancies
www.indiandentalacademy.com
 Line defects (dislocations)
www.indiandentalacademy.com
 Planar defects (grain boundaries in
metals)
Orientation of space lattice of each grain.
Structure of grain proper & grai...
SURFACE ENERGY
 The increase in the energy per unit area of
surface is referred as the surface energy
or surface tension....
 Factors affecting the surface energy
Available functional groups.
Type of crystal plane of a space lattice
present at th...
Adhesion & Bonding
 Adhesive force - like molecules.
 Cohesive force - unlike molecules.
 Adhesive.
 Adherend.
 Chemi...
BASIC METALLURGICAL TERMS
 What is a metal?
Any chemical element that ionises (+vely )
in solution is known as metal.
 W...
 What is an cast
metal?
Solidification of pure
metal.
 What is an wrought
metal?
Wires are made from
castings by drawing...
HISTORY OF STAINLESS STEEL
 In the year 1740 Beryamin Huntsman.
 In the year 1913,a break through came
when Brearly of S...
CLASSIFICATION
 Based on lattice arrangements
Ferritic (bcc)
Austenitic (fcc)
Martenistic (bct)
 Based on carbon content...
 Acc to American iron and steel institute
300 – 502
 Acc to Andereson
Soft
Half-hard
Hard
 ANSI/ADA specification no 32...
PROPERTIES BASED ON
LATTICE ARRANGEMENTS
 Ferritic (AISI-400)
Good corrosion
resistance.
Not hardenable by
heat treatment...
Austenitic(AISI-302),18-8 stainless steel.
 Type 304(0.08%),Type 316L(0.03%).
 Greater ductility and ability.
 Substant...
SENSITIZATION (weld decay)
 When 18-8 stainless steel is heated to
4000
-9000
c.
 Formation of chromium carbide at grain...
STABILIZATION
 Theoretical stand point reduce the carbon
content such that carbide precipitation
does not occur.
 The me...
DEFORMATION OF METALS
 From the physical properties of the metals
two types of deformation may exist.
Stresses below the ...
COLD WORKING
 Also known as strain hardening/work hardening.
 In a poly crystalline material.
 Over a period of time gr...
ANNEALING
 Effects associated with cold working can
be reversed by heating the metal.
 Severe the cold working ,more rea...
www.indiandentalacademy.com
MANUFACTURING OF
ORTHODONTIC WIRES
www.indiandentalacademy.com
DESIRABLE PROPERTIES
 Wires should have good modulus of
elasticity.
 low constant forces.
 Large elastic deflections.
...
MECHANICAL PROPPERTIES
Stress and strain.
 The internal force divided by the area over which
it acts within the body is t...
 Elastic limit
 Proportional limit
 Yield strength
www.indiandentalacademy.com
MODULUS OF ELASTICITY :
YOUNGS MODULUS(ELASTIC
MODULE)
 Ratio of stress to strain.
 The slope of this ratio indicates th...
 Flexibility
 Resilience
 Spring back (range of
action)
 Formability
www.indiandentalacademy.com
 Hardness
Property used to predict the wear
resistance of a material.
 Toughness
Property of being difficult to break.
...
 Stress relaxation
Change in the stress over a period of time.
 Zero stress relaxation
In a deflected wire ,if the stres...
Ductility
 Ability to with stand
under a tensile load.
 The relative ease in
which a metal can be
drawn into wire.
 Dep...
HEAT TREATMENT OF ALLOYS
Softening.
 Electric furnace for 10
mins at 7000
c &
quenched in water.
 Indicated for
structur...
METAL JOINING OPERATIONS
 Soldering.
 Brazing.
 welding.
www.indiandentalacademy.com
PARAMETERS GOVERING THE
PROCEDURE
 Parent metal.
 Flux.
 Brazing filler metal.
 Heat source.
 Methods of soldering.
w...
FLUX
 Latin word means to flow.
 Purpose is to remove any oxide layer on
the parent metal.
 Based on their action
Prote...
 Anti-flux .
Graphite, rouge (iron oxide) or whiting
(calcium carbonate)
www.indiandentalacademy.com
TYPES OF SOLDERS
Soft
 Lead-tin alloys.
 Low melting point.
 Lack corrosion
resistance.
Hard
 Silver, copper, zinc,
ca...
PROPERTIES OF A SOLDER
 Appropriate flow temperature.
 Ability to wet the parent metal.
 Sufficient fluidity.
 Good co...
HEAT SOURCE
 A gas-air or gas-oxygen torch.
 Gases commonly used,
Hydrogen.
Natural gas.
Propane.
Acetylene.
www.indiand...
OVEN(FURNACE BRAZING)
 Provides an heated surroundings.
 Less heat is lost as compared to torch
brazing.
 Transmission ...
METHODS OF SOLDERING
 Free hand soldering.
 Investment soldering.
 Infra red soldering.
1000 watt tungsten filament qua...
WELDING
 A portion of metal being joined is melted &
flowed together.
 Joining of flat structures.
 A nugget of re-soli...
PARTS OF A TYPICAL WELDER
Heat generated=KI2
RTwww.indiandentalacademy.com
THANK YOU
For more details please visit
www.indiandentalacademy.com
www.indiandentalacademy.com
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Stainless steel soldering & welding /certified fixed orthodontic courses by Indian dental academy

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The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and offering a wide range of dental certified courses in different formats.

Indian dental academy provides dental crown & Bridge,rotary endodontics,fixed orthodontics,
Dental implants courses.for details pls visit www.indiandentalacademy.com ,or call
0091-9248678078

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Stainless steel soldering & welding /certified fixed orthodontic courses by Indian dental academy

  1. 1. STAINLESS STEEL, SOLDERING AND WELDING www.indiandentalacademy.com INDIAN DENTAL ACADEMY Leader in continuing dental education www.indiandentalacademy.com
  2. 2. STRUCTURE OF MATTER  Study of dental materials and its properties particularily of solids.  Basic materials used in the field of Dentistry.  Collective reaction of these atoms, whether physical or chemical determine the effectiveness of an material. www.indiandentalacademy.com
  3. 3. INTER ATOMIC BONDS  PRIMARY BONDS Ionic bonds Covalent bonds Metallic bonds www.indiandentalacademy.com
  4. 4.  SECONDARY BONDS (Vander waals force) www.indiandentalacademy.com
  5. 5. EQUILIBRIUM INTER ATOMIC DISTANCE  Limiting factor for the atoms & molecules from approaching each other too closely.  Boundaries & volumes of an atom are not discrete instead they are vague determined by their electrostatic fields. www.indiandentalacademy.com
  6. 6.  Forces of attraction versus forces of repulsion dictating the equilibrium position of the atoms. www.indiandentalacademy.com
  7. 7. CRYSTAL STRUCTURE  UnitCell-smallest repeating unit that is contained in a crystal.  SpaceLattice-any arrangement of atoms in space such that every atom is situated similarly to every other atom. www.indiandentalacademy.com
  8. 8. BCC FCC HCP www.indiandentalacademy.com
  9. 9. CRYSTAL IMPERFECTIONS  Point defects Impurities vacancies www.indiandentalacademy.com
  10. 10.  Line defects (dislocations) www.indiandentalacademy.com
  11. 11.  Planar defects (grain boundaries in metals) Orientation of space lattice of each grain. Structure of grain proper & grain boundaries are they same? Grain boundaries a region of transition. Non crystalline. High energy. Tendency towards amorphism. www.indiandentalacademy.com
  12. 12. SURFACE ENERGY  The increase in the energy per unit area of surface is referred as the surface energy or surface tension.  Surface energy of a solid is greater than its interior. www.indiandentalacademy.com
  13. 13.  Factors affecting the surface energy Available functional groups. Type of crystal plane of a space lattice present at the surface. www.indiandentalacademy.com
  14. 14. Adhesion & Bonding  Adhesive force - like molecules.  Cohesive force - unlike molecules.  Adhesive.  Adherend.  Chemisorption. www.indiandentalacademy.com
  15. 15. BASIC METALLURGICAL TERMS  What is a metal? Any chemical element that ionises (+vely ) in solution is known as metal.  What is an alloy? A solid mixture of two or more metals. www.indiandentalacademy.com
  16. 16.  What is an cast metal? Solidification of pure metal.  What is an wrought metal? Wires are made from castings by drawing a cast metal through die. certain metallurgical characteristics not associated with cast structure. www.indiandentalacademy.com
  17. 17. HISTORY OF STAINLESS STEEL  In the year 1740 Beryamin Huntsman.  In the year 1913,a break through came when Brearly of Shiffield.  Introduction of chromium steel to the field of orthodontics by Friel of Ireland in 1933.  Steel is an iron based alloy that contains carbon less than 1.2%.  When chromium is added to steel the alloy is called stainless steel(12%-30%). www.indiandentalacademy.com
  18. 18. CLASSIFICATION  Based on lattice arrangements Ferritic (bcc) Austenitic (fcc) Martenistic (bct)  Based on carbon content(0.8%) Hypo-eutectoid Hyper-eutectoid www.indiandentalacademy.com
  19. 19.  Acc to American iron and steel institute 300 – 502  Acc to Andereson Soft Half-hard Hard  ANSI/ADA specification no 32 Type 1 (low-resilience) Type 2 (high-resilience) www.indiandentalacademy.com
  20. 20. PROPERTIES BASED ON LATTICE ARRANGEMENTS  Ferritic (AISI-400) Good corrosion resistance. Not hardenable by heat treatment. Not readily work hardenable. Finds little application in dentistry.  Martensitic(AISI-400) Can be heat treated. High strength & hardness. Used in surgical & cutting instruments. www.indiandentalacademy.com
  21. 21. Austenitic(AISI-302),18-8 stainless steel.  Type 304(0.08%),Type 316L(0.03%).  Greater ductility and ability.  Substantial strengthening.  Ease of welding  Readily over comes sensitization  Less critical grain growth  Ease in forming www.indiandentalacademy.com
  22. 22. SENSITIZATION (weld decay)  When 18-8 stainless steel is heated to 4000 -9000 c.  Formation of chromium carbide at grain boundaries highest at 6500 c.  An inter- granular corrosion occurs and a partial disintegration of the metal may occur. www.indiandentalacademy.com
  23. 23. STABILIZATION  Theoretical stand point reduce the carbon content such that carbide precipitation does not occur.  The method most commonly employed is introduction of titanium approximately 6 times the carbon content. www.indiandentalacademy.com
  24. 24. DEFORMATION OF METALS  From the physical properties of the metals two types of deformation may exist. Stresses below the proportional limit. Stresses above the proportional limit. www.indiandentalacademy.com
  25. 25. COLD WORKING  Also known as strain hardening/work hardening.  In a poly crystalline material.  Over a period of time greater stress is required to produce the further slip.  Metal becomes stronger and harder.  As a result surface hardness, strength & proportional limit are increased, where as the ductility & resistance to corrosion are decreased.  Elastic modulus remains the same. www.indiandentalacademy.com
  26. 26. ANNEALING  Effects associated with cold working can be reversed by heating the metal.  Severe the cold working ,more readily does annealing occur.  In general comprises of three stages recovery, recrystallisation and grain growth.  Higher the melting point of the metal higher is the temp needed for annealing. www.indiandentalacademy.com
  27. 27. www.indiandentalacademy.com
  28. 28. MANUFACTURING OF ORTHODONTIC WIRES www.indiandentalacademy.com
  29. 29. DESIRABLE PROPERTIES  Wires should have good modulus of elasticity.  low constant forces.  Large elastic deflections.  Ease of joining.  Good tarnish & corrosion resistance.  Good formability. www.indiandentalacademy.com
  30. 30. MECHANICAL PROPPERTIES Stress and strain.  The internal force divided by the area over which it acts within the body is the resultant stress.  The deformation is called strain.  Depending on their direction they are classified into three types, Tensile stress Compressive stress Shear stress Complex stress www.indiandentalacademy.com
  31. 31.  Elastic limit  Proportional limit  Yield strength www.indiandentalacademy.com
  32. 32. MODULUS OF ELASTICITY : YOUNGS MODULUS(ELASTIC MODULE)  Ratio of stress to strain.  The slope of this ratio indicates the relative stiffness and the springiness of a wire.  Wire with low modulus of elasticity has increased flexibility as compared to a wire of high modulus of elasticity. www.indiandentalacademy.com
  33. 33.  Flexibility  Resilience  Spring back (range of action)  Formability www.indiandentalacademy.com
  34. 34.  Hardness Property used to predict the wear resistance of a material.  Toughness Property of being difficult to break.  Brittleness Opposite of toughness, indicates the material is apt to fracture at or near its proportional limit. www.indiandentalacademy.com
  35. 35.  Stress relaxation Change in the stress over a period of time.  Zero stress relaxation In a deflected wire ,if the stress does not reduce and wire still exists a constant force. www.indiandentalacademy.com
  36. 36. Ductility  Ability to with stand under a tensile load.  The relative ease in which a metal can be drawn into wire.  Dependent on tensile strength. Malleability  Ability to with stand under compression.  Increases with increase in temp.  The relative ease in which a metal can be drawn into sheet. www.indiandentalacademy.com
  37. 37. HEAT TREATMENT OF ALLOYS Softening.  Electric furnace for 10 mins at 7000 c & quenched in water.  Indicated for structures that are to be ground, shaped or cold worked. Hardening.  Heated for 15-30 mins.  Temp depends upon the alloy composition.  Generally ranges from 2000 c-4500 c. www.indiandentalacademy.com
  38. 38. METAL JOINING OPERATIONS  Soldering.  Brazing.  welding. www.indiandentalacademy.com
  39. 39. PARAMETERS GOVERING THE PROCEDURE  Parent metal.  Flux.  Brazing filler metal.  Heat source.  Methods of soldering. www.indiandentalacademy.com
  40. 40. FLUX  Latin word means to flow.  Purpose is to remove any oxide layer on the parent metal.  Based on their action Protective Reducing Solvent  Type1 (low temp glass)  Type 2(reducing) www.indiandentalacademy.com
  41. 41.  Anti-flux . Graphite, rouge (iron oxide) or whiting (calcium carbonate) www.indiandentalacademy.com
  42. 42. TYPES OF SOLDERS Soft  Lead-tin alloys.  Low melting point.  Lack corrosion resistance. Hard  Silver, copper, zinc, cadmium.  High melting point.  Gold & silver solders.  Have good tarnish & corrosion resistance. www.indiandentalacademy.com
  43. 43. PROPERTIES OF A SOLDER  Appropriate flow temperature.  Ability to wet the parent metal.  Sufficient fluidity.  Good contrast. www.indiandentalacademy.com
  44. 44. HEAT SOURCE  A gas-air or gas-oxygen torch.  Gases commonly used, Hydrogen. Natural gas. Propane. Acetylene. www.indiandentalacademy.com
  45. 45. OVEN(FURNACE BRAZING)  Provides an heated surroundings.  Less heat is lost as compared to torch brazing.  Transmission of heat from the heating elements to the working area.  Convection.  Conduction.  Radiant heat. www.indiandentalacademy.com
  46. 46. METHODS OF SOLDERING  Free hand soldering.  Investment soldering.  Infra red soldering. 1000 watt tungsten filament quartz iodine bulb. Mounted at the primary focal point of a gold plated elliptical reflector.www.indiandentalacademy.com
  47. 47. WELDING  A portion of metal being joined is melted & flowed together.  Joining of flat structures.  A nugget of re-solidified cast structure.  Strength of the joint depends on the area of weld.  Pioneer work in this field was done by Friel1933&McKeag1939. www.indiandentalacademy.com
  48. 48. PARTS OF A TYPICAL WELDER Heat generated=KI2 RTwww.indiandentalacademy.com
  49. 49. THANK YOU For more details please visit www.indiandentalacademy.com www.indiandentalacademy.com

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