rivet and riveted joints.pptx

7/27/2019 rivet and riveted joints.pptx

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A Brief Study on Rivet and Riveted

Group Present

Deep Praka

Kumar Nish

Sa

Yami

Pransh


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What is Rivet

A rivet is a round rod of circular cross section. It consist of twHEAD and SHANK.

Metals Commonly used for rivets are mild steel, wrought Ironand Aluminium alloys etc.


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What is Riveting ?

Riveting is the process of forming a rivjoint. For this, a rivet is first placed in twhole drill through the two parts to bthen the shank end is made into a rivehead by applying pressure.


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Process of Riveting


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Caulking and Fullering

Caulking: Operation of burring

down the edges of the plates

and heads of the rivets to form

a metal to metal joint

Fullering is a better option


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TYPES OF RIVET HEADS

Indian standard heads for general purposes(length of shank=2.5D to 10 D )

(see:1929 and :2155 for preffered length combination)


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Types of Riveted Joints There are two types of riveted joints.

1. Riveted Lap Joint :- In lap Joints oneplate overlaps the other and indrawing are shown in differentplanes. All the rivet pass throughboth plates. The Joint is known assingle riveted. If there is one row ofrivets then it is called single riveted.If there are two rows of rivets thenit is called double riveted.

Lap joint

(a): Single

rivet lap joint

Rivet location

Rivets

b): Double riveted

l(lap joint, chain


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Riveted butt Joint :- In buttjoints ends of the main platesbutt up against each other and

may be considered as lying inthe same plane. One or twostrap or cover plates are placedover the joint and riveted toeach plate. If there is one coverplate it is known as single strapbutt joint and if there are twocover plate it is known asdouble strap butt joint.

Butt Joints are stronger than lap Joints and are generally

Used for joining thick plates

Butt joint


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Use of Rivets :-

Rivets joints are permanent fastenings and riveting is one ofcommonly used method of producing rigid and permanent jManufacturing of boilers, storage tanks, etc.

These joints are also used to fasten rolled steel sections in sworks, such as bridge and roof trusses.


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Important Terms Used in Riveted Joints The following terms in connection with the riveted joints are important fro

point of view :

1. Pitch. It is the distance from the centre of one rivet to the centre of the ne

parallel to the seam as shown in Fig. It is usually denoted byp.

2. Transverse pitch. It is the perpendicular distance between the centre lines orows as shown in Fig. It is usually denoted bypt

3. Diagonal pitch. It is the distance between the centres of the rivets in adjaceriveted joint as shown in Fig. It is usually denoted bypd.

4. Margin or marginal pitch. It is the distance between the centre of rivet holedge of the plate as shown in Fig. It is usually denoted by m.


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CASES OF FALIURE OF RIVETS

Under tensile strength or tearing resistance of plate per pitcP(t) = (p-d)*t*f(t)

Where,

P = Tearing resistance of plate per pitch

p = Pitch

t = Thickness of plate

f(t) = permissible tearing strength


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CASES OF FALIURE OF RIVETS

Under shearing resistance of plate per pitchRivet resistance to shear = (/4)d*d*f(s)

P(s) = (/4)d*d*f(s)

Where,

P(s) = shearing resistance of plate per pitch

d = Diameter of rivet hole

f(s) = permissible shearing strength


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CASES OF FALIURE OF RIVET

Under crushing resistance of plate per pitch.P(c) = (nd)*t*f(c)

Where,

P(c) = Tearing resistance of plate per pitch

n = no of rows of rivet

t = thickness of plate

f(c) = permissible crushing strength

Emprical Proportions of dimensions of riveted joints


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Emprical Proportions of dimensions of riveted joints Diameter of rivets.

the diameter of the rivet hole (d) may be determined by using

Thickness of plate

t = Thickness of the plate

Distance of centre of the rivet from edge of the plate = 1.5d

Margin , m=d

Longitudinal Pitch p=3d Transverse pitch pt = 0.8P for chain riveting

= 0.6P for zig-zag riveting

Thickness of butt strap.

Single cover plate t1 = 1.125 t

Double cover plate t2 = 0.7 to 0.8t


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PROPER DIMENSIONING OF RIVETSIMPROVING ITS FAILURE DEFECTS

We can do proper

dimensioning of rivets after

Studying and improving its

failure defects..


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EFFICIENCY OF RIVET JOINT

= Least value of P(t),P(s),P(c)

Strength of un-riveted plate

Where,

Strength of un-riveted plate = (t)*pt

JOINTS

DISADVANTAGES OF LAP


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DISADVANTAGES OF LAPAND SINGLE STRAP BUTTJOINT The disadvantages in lap joint is that when

the plates are in tension owing to their notbeing in the same plane, a couple actsabout the rivets, tending to bend the joint.

The single strap butt joint also suffers thesame problem. Beside, this joint has further

disadvantage that it can be caulked only onone side and therefore, single strap butt

joints should never be used for boilerpurposes.

Even in other applications it is rarely used.


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rivet and riveted joints.pptx

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