Short Notes: Bolted, Riveted and Welded Joints | Short Notes for Mechanical Engineering PDF Download

 Page 1


Bolted, Riveted and Welded Joints  
The means to keep the two things together is known as Joint.
There are two basic components of any joint: The components to be joined, and
Fastener or joining elements.
Types of Joints: Permanent Joints, Semi-Permanent Joints, and Temporary Joints.
• If the joined or fastened element joint can not open or separated without 
causing any damage them, then joint is known as permanent joint. Like 
Welded Joints.
• If the joined or fastened element joint can open or separated with a marginal 
damage to any one of the joined parts, then joint is known as semi-permanent 
joint. Like Riveted Joints.
• If the joined or fastened element joint can open or separated without causing 
any damage them, then joint is known as temporary joints. Like Bolted Joints.
Riveted joints:
• Components of Riveted Joints:
° There are two basic components of riveted joints: Rivets and Two or 
more plates.
• Rivet is a cylindrical bar having a head and tail portion as its integral part.
• Material Used for Rivets:
° The rivet head are made by the following two methods: Cold Heading 
and Hot forging.
° Therefore the material of the rivets must possess the sufficient 
DUCTILITY and TOUGHNESS.
Page 2


Bolted, Riveted and Welded Joints  
The means to keep the two things together is known as Joint.
There are two basic components of any joint: The components to be joined, and
Fastener or joining elements.
Types of Joints: Permanent Joints, Semi-Permanent Joints, and Temporary Joints.
• If the joined or fastened element joint can not open or separated without 
causing any damage them, then joint is known as permanent joint. Like 
Welded Joints.
• If the joined or fastened element joint can open or separated with a marginal 
damage to any one of the joined parts, then joint is known as semi-permanent 
joint. Like Riveted Joints.
• If the joined or fastened element joint can open or separated without causing 
any damage them, then joint is known as temporary joints. Like Bolted Joints.
Riveted joints:
• Components of Riveted Joints:
° There are two basic components of riveted joints: Rivets and Two or 
more plates.
• Rivet is a cylindrical bar having a head and tail portion as its integral part.
• Material Used for Rivets:
° The rivet head are made by the following two methods: Cold Heading 
and Hot forging.
° Therefore the material of the rivets must possess the sufficient 
DUCTILITY and TOUGHNESS.
• The popular materials for the rivets are: Steel, Brass, Aluminium & Conner as 
per the requirement of the application for fluid tight joints the steel rivets are 
used
Advantages of Riveted Joints:
• Production rates are high.
• Initial and maintenance costs for equipment are low.
• Either metallic or non-metallic materials can be joined.
• Dissimilar metals and assemblies having a number of parts with non uniform 
thickness can readily be fastened.
• Unskilled labor can be used to operate equipment.
• The rivets can be made of variety of material ranging from monel or inconel to 
lead or zinc.
• The rivets can be used not only as a fastener but as a pivot or other functional 
component.
Limitations of Riveted Joints:
• In riveted joints the parts once fastened can not be easily dissembled.
• The riveted joints are not as fluid tight as welded joints.
• The riveted joints weaken the parts to be connected.
• The complicated components can not be riveted.
• The riveted joints can not be produced as fast as welded joints.
• As compared to welded joints the riveted joints lead to bulky construction.
• The protruding rivet heads are inconvenient and undesirable in many 
applications.
Welded Joints
• It is a permanent joint.
• When the two parts are joined by heating to a suitable temperature with or 
without application of pressure.
• It is lighter than riveted joint, great strength, maximum efficiency.
Welding Processes
• If two rods have to joined then we have to adopt the welding process with 
which two or more rods can be joined together.
• Fusion Welding
° In case of fusion welding the parts to be jointed are held in position 
while the molten metal is supplied to the joint. The molten metal may 
come from the parts themselves (/'.e., parent metal) or filler metal which 
normally have the composition of the parent metal. The joint surface 
become plastic or even molten because of the heat from the molten filler 
or other source.
° Thus, when the molten metal solidifies or fuses, the joint is formed.
• Thermit Welding
° In thermit welding, a moisture of iron oxide and aluminium called Thermit 
is ignited and the iron oxide is reduced to molten iron. The molten iron is
Page 3


Bolted, Riveted and Welded Joints  
The means to keep the two things together is known as Joint.
There are two basic components of any joint: The components to be joined, and
Fastener or joining elements.
Types of Joints: Permanent Joints, Semi-Permanent Joints, and Temporary Joints.
• If the joined or fastened element joint can not open or separated without 
causing any damage them, then joint is known as permanent joint. Like 
Welded Joints.
• If the joined or fastened element joint can open or separated with a marginal 
damage to any one of the joined parts, then joint is known as semi-permanent 
joint. Like Riveted Joints.
• If the joined or fastened element joint can open or separated without causing 
any damage them, then joint is known as temporary joints. Like Bolted Joints.
Riveted joints:
• Components of Riveted Joints:
° There are two basic components of riveted joints: Rivets and Two or 
more plates.
• Rivet is a cylindrical bar having a head and tail portion as its integral part.
• Material Used for Rivets:
° The rivet head are made by the following two methods: Cold Heading 
and Hot forging.
° Therefore the material of the rivets must possess the sufficient 
DUCTILITY and TOUGHNESS.
• The popular materials for the rivets are: Steel, Brass, Aluminium & Conner as 
per the requirement of the application for fluid tight joints the steel rivets are 
used
Advantages of Riveted Joints:
• Production rates are high.
• Initial and maintenance costs for equipment are low.
• Either metallic or non-metallic materials can be joined.
• Dissimilar metals and assemblies having a number of parts with non uniform 
thickness can readily be fastened.
• Unskilled labor can be used to operate equipment.
• The rivets can be made of variety of material ranging from monel or inconel to 
lead or zinc.
• The rivets can be used not only as a fastener but as a pivot or other functional 
component.
Limitations of Riveted Joints:
• In riveted joints the parts once fastened can not be easily dissembled.
• The riveted joints are not as fluid tight as welded joints.
• The riveted joints weaken the parts to be connected.
• The complicated components can not be riveted.
• The riveted joints can not be produced as fast as welded joints.
• As compared to welded joints the riveted joints lead to bulky construction.
• The protruding rivet heads are inconvenient and undesirable in many 
applications.
Welded Joints
• It is a permanent joint.
• When the two parts are joined by heating to a suitable temperature with or 
without application of pressure.
• It is lighter than riveted joint, great strength, maximum efficiency.
Welding Processes
• If two rods have to joined then we have to adopt the welding process with 
which two or more rods can be joined together.
• Fusion Welding
° In case of fusion welding the parts to be jointed are held in position 
while the molten metal is supplied to the joint. The molten metal may 
come from the parts themselves (/'.e., parent metal) or filler metal which 
normally have the composition of the parent metal. The joint surface 
become plastic or even molten because of the heat from the molten filler 
or other source.
° Thus, when the molten metal solidifies or fuses, the joint is formed.
• Thermit Welding
° In thermit welding, a moisture of iron oxide and aluminium called Thermit 
is ignited and the iron oxide is reduced to molten iron. The molten iron is
poured into a mould made around the joint and fuses with the parts to b|e 
welded.
• Gas Welding
o A gas welding is made by applying the flame of an oxy-acetylene or 
hydrogen gas from a welding torch upon the surfaces of the prepared 
joint.
• Electric Arc Welding
o In electric arc welding, the work is prepared in the same manner as for 
gas welding.
° In this case the filler metal is supplied by metal welding electrode. The 
base metal in the path of the arc stream is melted, forming a pool of 
molten metal, which seems to be forced out of the pool by the blast from 
the arc
• Forge Welding
° In this type of welding, first the parts are to be heated about a suitable 
temperature and then they hammered to form a joint.
Types of Welded Joints: There are two types of welded joint
• Lap Joint or Fillet Joint
• Butt Joint
Lap Joint or Fillet Joint
• In lap joint, overlapping the plate and welding the edge of the plates takes 
place in welding process.
• The strength of different types of fillet joint can be given according to their 
welding process as
° Strength of Parallel Fillet Joint
t = h cos 45°, t = 0.707 h
• Shear strength in parallel fillet weld,
r = — - — o rP - 0.707h ir 
0.707 h i
where P = Tensile force on the plates 
h = Leg of the weld 
/ = Length of the weld 
t = Permissible shear stress
Parallel fillet joint
For double parallel fillet weld, P = 1.414 h/r
Page 4


Bolted, Riveted and Welded Joints  
The means to keep the two things together is known as Joint.
There are two basic components of any joint: The components to be joined, and
Fastener or joining elements.
Types of Joints: Permanent Joints, Semi-Permanent Joints, and Temporary Joints.
• If the joined or fastened element joint can not open or separated without 
causing any damage them, then joint is known as permanent joint. Like 
Welded Joints.
• If the joined or fastened element joint can open or separated with a marginal 
damage to any one of the joined parts, then joint is known as semi-permanent 
joint. Like Riveted Joints.
• If the joined or fastened element joint can open or separated without causing 
any damage them, then joint is known as temporary joints. Like Bolted Joints.
Riveted joints:
• Components of Riveted Joints:
° There are two basic components of riveted joints: Rivets and Two or 
more plates.
• Rivet is a cylindrical bar having a head and tail portion as its integral part.
• Material Used for Rivets:
° The rivet head are made by the following two methods: Cold Heading 
and Hot forging.
° Therefore the material of the rivets must possess the sufficient 
DUCTILITY and TOUGHNESS.
• The popular materials for the rivets are: Steel, Brass, Aluminium & Conner as 
per the requirement of the application for fluid tight joints the steel rivets are 
used
Advantages of Riveted Joints:
• Production rates are high.
• Initial and maintenance costs for equipment are low.
• Either metallic or non-metallic materials can be joined.
• Dissimilar metals and assemblies having a number of parts with non uniform 
thickness can readily be fastened.
• Unskilled labor can be used to operate equipment.
• The rivets can be made of variety of material ranging from monel or inconel to 
lead or zinc.
• The rivets can be used not only as a fastener but as a pivot or other functional 
component.
Limitations of Riveted Joints:
• In riveted joints the parts once fastened can not be easily dissembled.
• The riveted joints are not as fluid tight as welded joints.
• The riveted joints weaken the parts to be connected.
• The complicated components can not be riveted.
• The riveted joints can not be produced as fast as welded joints.
• As compared to welded joints the riveted joints lead to bulky construction.
• The protruding rivet heads are inconvenient and undesirable in many 
applications.
Welded Joints
• It is a permanent joint.
• When the two parts are joined by heating to a suitable temperature with or 
without application of pressure.
• It is lighter than riveted joint, great strength, maximum efficiency.
Welding Processes
• If two rods have to joined then we have to adopt the welding process with 
which two or more rods can be joined together.
• Fusion Welding
° In case of fusion welding the parts to be jointed are held in position 
while the molten metal is supplied to the joint. The molten metal may 
come from the parts themselves (/'.e., parent metal) or filler metal which 
normally have the composition of the parent metal. The joint surface 
become plastic or even molten because of the heat from the molten filler 
or other source.
° Thus, when the molten metal solidifies or fuses, the joint is formed.
• Thermit Welding
° In thermit welding, a moisture of iron oxide and aluminium called Thermit 
is ignited and the iron oxide is reduced to molten iron. The molten iron is
poured into a mould made around the joint and fuses with the parts to b|e 
welded.
• Gas Welding
o A gas welding is made by applying the flame of an oxy-acetylene or 
hydrogen gas from a welding torch upon the surfaces of the prepared 
joint.
• Electric Arc Welding
o In electric arc welding, the work is prepared in the same manner as for 
gas welding.
° In this case the filler metal is supplied by metal welding electrode. The 
base metal in the path of the arc stream is melted, forming a pool of 
molten metal, which seems to be forced out of the pool by the blast from 
the arc
• Forge Welding
° In this type of welding, first the parts are to be heated about a suitable 
temperature and then they hammered to form a joint.
Types of Welded Joints: There are two types of welded joint
• Lap Joint or Fillet Joint
• Butt Joint
Lap Joint or Fillet Joint
• In lap joint, overlapping the plate and welding the edge of the plates takes 
place in welding process.
• The strength of different types of fillet joint can be given according to their 
welding process as
° Strength of Parallel Fillet Joint
t = h cos 45°, t = 0.707 h
• Shear strength in parallel fillet weld,
r = — - — o rP - 0.707h ir 
0.707 h i
where P = Tensile force on the plates 
h = Leg of the weld 
/ = Length of the weld 
t = Permissible shear stress
Parallel fillet joint
For double parallel fillet weld, P = 1.414 h/r
• Strength of Transverse Fillet Weld
o p = Throat area Allowable tensile stress 
° = 0.707 s * I * ot
For double transverse fillet joint P = 1.414 hlat
67.5°
Transverse fillet weld
Special Cases of Fillet Welded Joint
The following are the considerations when the fillet welded joints are subjected to 
some forces (i.e., torsion and bending)
• Circular Fillet Weld Subjected to Torsion
Shear stress
r = — tt 
ntd
or
2.8 IT
T = --------
n »x 7 j 2
7 cha
where T = Torque acting or rod 
h = size of the weld 
t = Throat thickness
Circular Fillet Weld Subjected to Bending Moment 
• Bending stress
4.1/
7 itd~
5.66 M 
nhd~
Page 5


Bolted, Riveted and Welded Joints  
The means to keep the two things together is known as Joint.
There are two basic components of any joint: The components to be joined, and
Fastener or joining elements.
Types of Joints: Permanent Joints, Semi-Permanent Joints, and Temporary Joints.
• If the joined or fastened element joint can not open or separated without 
causing any damage them, then joint is known as permanent joint. Like 
Welded Joints.
• If the joined or fastened element joint can open or separated with a marginal 
damage to any one of the joined parts, then joint is known as semi-permanent 
joint. Like Riveted Joints.
• If the joined or fastened element joint can open or separated without causing 
any damage them, then joint is known as temporary joints. Like Bolted Joints.
Riveted joints:
• Components of Riveted Joints:
° There are two basic components of riveted joints: Rivets and Two or 
more plates.
• Rivet is a cylindrical bar having a head and tail portion as its integral part.
• Material Used for Rivets:
° The rivet head are made by the following two methods: Cold Heading 
and Hot forging.
° Therefore the material of the rivets must possess the sufficient 
DUCTILITY and TOUGHNESS.
• The popular materials for the rivets are: Steel, Brass, Aluminium & Conner as 
per the requirement of the application for fluid tight joints the steel rivets are 
used
Advantages of Riveted Joints:
• Production rates are high.
• Initial and maintenance costs for equipment are low.
• Either metallic or non-metallic materials can be joined.
• Dissimilar metals and assemblies having a number of parts with non uniform 
thickness can readily be fastened.
• Unskilled labor can be used to operate equipment.
• The rivets can be made of variety of material ranging from monel or inconel to 
lead or zinc.
• The rivets can be used not only as a fastener but as a pivot or other functional 
component.
Limitations of Riveted Joints:
• In riveted joints the parts once fastened can not be easily dissembled.
• The riveted joints are not as fluid tight as welded joints.
• The riveted joints weaken the parts to be connected.
• The complicated components can not be riveted.
• The riveted joints can not be produced as fast as welded joints.
• As compared to welded joints the riveted joints lead to bulky construction.
• The protruding rivet heads are inconvenient and undesirable in many 
applications.
Welded Joints
• It is a permanent joint.
• When the two parts are joined by heating to a suitable temperature with or 
without application of pressure.
• It is lighter than riveted joint, great strength, maximum efficiency.
Welding Processes
• If two rods have to joined then we have to adopt the welding process with 
which two or more rods can be joined together.
• Fusion Welding
° In case of fusion welding the parts to be jointed are held in position 
while the molten metal is supplied to the joint. The molten metal may 
come from the parts themselves (/'.e., parent metal) or filler metal which 
normally have the composition of the parent metal. The joint surface 
become plastic or even molten because of the heat from the molten filler 
or other source.
° Thus, when the molten metal solidifies or fuses, the joint is formed.
• Thermit Welding
° In thermit welding, a moisture of iron oxide and aluminium called Thermit 
is ignited and the iron oxide is reduced to molten iron. The molten iron is
poured into a mould made around the joint and fuses with the parts to b|e 
welded.
• Gas Welding
o A gas welding is made by applying the flame of an oxy-acetylene or 
hydrogen gas from a welding torch upon the surfaces of the prepared 
joint.
• Electric Arc Welding
o In electric arc welding, the work is prepared in the same manner as for 
gas welding.
° In this case the filler metal is supplied by metal welding electrode. The 
base metal in the path of the arc stream is melted, forming a pool of 
molten metal, which seems to be forced out of the pool by the blast from 
the arc
• Forge Welding
° In this type of welding, first the parts are to be heated about a suitable 
temperature and then they hammered to form a joint.
Types of Welded Joints: There are two types of welded joint
• Lap Joint or Fillet Joint
• Butt Joint
Lap Joint or Fillet Joint
• In lap joint, overlapping the plate and welding the edge of the plates takes 
place in welding process.
• The strength of different types of fillet joint can be given according to their 
welding process as
° Strength of Parallel Fillet Joint
t = h cos 45°, t = 0.707 h
• Shear strength in parallel fillet weld,
r = — - — o rP - 0.707h ir 
0.707 h i
where P = Tensile force on the plates 
h = Leg of the weld 
/ = Length of the weld 
t = Permissible shear stress
Parallel fillet joint
For double parallel fillet weld, P = 1.414 h/r
• Strength of Transverse Fillet Weld
o p = Throat area Allowable tensile stress 
° = 0.707 s * I * ot
For double transverse fillet joint P = 1.414 hlat
67.5°
Transverse fillet weld
Special Cases of Fillet Welded Joint
The following are the considerations when the fillet welded joints are subjected to 
some forces (i.e., torsion and bending)
• Circular Fillet Weld Subjected to Torsion
Shear stress
r = — tt 
ntd
or
2.8 IT
T = --------
n »x 7 j 2
7 cha
where T = Torque acting or rod 
h = size of the weld 
t = Throat thickness
Circular Fillet Weld Subjected to Bending Moment 
• Bending stress
4.1/
7 itd~
5.66 M 
nhd~
Bending moment In circular fillet weld
Long Fillet Weld Subjected to Torsion
• Shear stress:
r =
37
IF
T
C S X
4.2427
hi1
Torsion in long fillet weld
Butt Joint
• The butt joint is the joint between two plates lying on same plane.
• In this type of joint, cutting, the members to the appropriate length and 
butting them together.
• Strength of Butt Joint
° For single V - butt joint, P = f x / x a,
° For double V-butt joint, P = (t7 + t2 )l*o t 
° Where, fi = Throat thickness at the top
f2 = Throat thickness at the bottom
Single V-butt joint Double V-butt joint
Axial Loaded Unsymmetrical Welded Joints
• The figure shows an angle section welded to a vertical beam by means of t 
parallel fillet weld 1 and 2, G is the centre of gravity of the angle section.
/ = /j + l2
P = Pl + P2
= l2 > '2