Answer: Dampness or moisture introduces hydrogen into the weld, which causes cracking when some metals are welded.
Explanation:
<em>This moisture (hydrogen) is a major cause of weld cracking and porosity. </em>
Answer:
Change in entropy S = 0.061
Second law of thermodynamics is satisfied since there is an increase in entropy
Explanation:
Heat Q = 300 kW
T2 = 24°C = 297 K
T1 = 7°C = 280 K
Change in entropy =
S = Q(1/T1 - 1/T2)
= 300(1/280 - 1/297) = 0.061
There is a positive increase in entropy so the second law is satisfied.
Answer:
The answer is "2 m/s".
Explanation:
The triangle from of the right angle:

Differentiating the above equation:



Answer:
See explanation below
Explanation:
Hypo-eutectoid steel has less than 0,8% of C in its composition.
It is composed by pearlite and α-ferrite, whereas Hyper-eutectoid steel has between 0.8% and 2% of C, composed by pearlite and cementite.
Ferrite has a higher tensile strength than cementite but cementite is harder.
Considering that hypoeutectoid steel contains ferrite at grain boundaries and pearlite inside grains whereas hypereutectoid steel contains a higher amount of cementite, the following properties are obtainable:
Hypo-eutectoid steel has higher yield strength than Hyper-eutectoid steel
Hypo-eutectoid steel is more ductile than Hyper-eutectoid steel
Hyper-eutectoid steel is harder than Hyper-eutectoid steel
Hypo-eutectoid steel has more tensile strength than Hyper-eutectoid steel.
When making a knife or axe blade, I would choose Hyper-eutectoid steel alloy because
1. It is harder
2. It has low cost
3. It is lighter
When making a die to press powders or stamp a softer metals, I will choose hypo-eutectoid steel alloy because
1. It is ductile
2. It has high tensile strength
3. It is durable
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