# The upper critical temperature for steel

1.  Varies according to carbon content in it

2.  Is constant

3.  Depends on the rate of heating

4.  None of these

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Varies according to carbon content in it

Explanation :
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# Temperature at which the change starts on heating the steel, is called

1.  Lower critical temperature

2.  Upper critical temperature

3.  Point of recalescence

4.  None of these

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Lower critical temperature

Explanation :
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# Temperature at which change ends on heating the steel, is called

1.  Lower critical temperature

2.  Upper critical temperature

3.  Point of recalescence

4.  None of these

4

Upper critical temperature

Explanation :
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# Steel containing 0.8% carbon has

1.  No critical point

2.  One critical point

3.  Two critical points

4.  Three critical points

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One critical point

Explanation :
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# Lower critical point for all steels is

1.  6000C

2.  7230C

3.  9000C

4.  91400 0C

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7230C

Explanation :
No Explanation available for this question

# Gamma iron exists in the temperature range of

1.  3000C to 6000C

2.  6000C to 9000C

3.  9000C to 14000C

4.   14000C to 15300C

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9000C to 14000C

Explanation :
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# Alpha iron exists at

1.  Below 7680C

2.  Between 7680C to 900 0C

3.  Between 9000C to 1400 0C

4.  Between 1400 0C to 1530 0C

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Below 7680C

Explanation :
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# Knoop hardness number (KHN) is equal to Where, L=length of long diagonal (mm) C=constant related to length of projected area

1.  P/LC

2.  P/L2C

3.  2P/LC

4.  2P/L2C

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Explanation :
No Explanation available for this question

# Delta iron exists in the temperature range of

1.  00C to 7680C

2.  7680Cto 9000C

3.  9000C to 14000C

4.  14000C to 15300C

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14000C to 15300C

Explanation :
No Explanation available for this question

# Alpha (α) iron

1.  Has body centered atomic arrangement

2.  Is commonly called ferrite

3.  Is magnetic

4.  All of these

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