Questions
The water quenched 1045 sample had a higher hardness and tensile strength than the air cooled...

The water quenched 1045 sample had a higher hardness and tensile strength than the air cooled sample? Explain in term of microstructural theory as to why this is the case.

In: Mechanical Engineering

If the weight of the contents in a vessel is measured and the density of the...

If the weight of the contents in a vessel is measured and the density of the material is known, fill in the blanks to describe what steps are required to determine level. Find the ____________________ by dividing weight by ____________________, and then find the ____________________ by dividing ____________________ by the ____________________ of the vessel.

Fill in the blanks?

In: Mechanical Engineering

1. Identify 7-10 primary functions of a common laptop computer. 2. Identify 7-10 primary parts/components of...

1. Identify 7-10 primary functions of a common laptop computer.
2. Identify 7-10 primary parts/components of a common laptop computer.
3. Allocate the functions in (a) to the parts/components in (b).

this is related to systems engineering

In: Mechanical Engineering

Discuss the crystal structure of martensite and how this affects its mechanical properties. Identify the advantages...

Discuss the crystal structure of martensite and how this affects its mechanical properties. Identify the advantages and disadvantages of this material, and suitable practical applications. (500 words

In: Mechanical Engineering

1.Explain how hot rolling can be used to manipulate the mechanical properties of metals, with respect...

1.Explain how hot rolling can be used to manipulate the mechanical properties of metals, with respect to grain structure. (500 words)

In: Mechanical Engineering

Groover/Introduction to Manufacturing Processes Casting Case Study: Kevin Working in Detroit Kevin was very excited about...

Groover/Introduction to Manufacturing Processes

Casting Case Study: Kevin Working in Detroit

Kevin was very excited about his new engineering job near Detroit. He was finally going to be able to contribute to the next generation of automobile design for one of the world’s largest carmakers. Even better, his first project was in development of a new-model hydrogen-fueled sports car. The assignment involved product and process design for three large frame-type structural components for the front half of the car.

Since the parts would eventually be needed in fairly high volume, Kevin figured a net shape process such as casting would be the only economical approach for production. Although cast iron is definitely the best structural material for casting, the demands of the part required the strength and toughness of steel. Kevin’s boss agreed and told Kevin to get started on completing the remaining design details for the parts and getting the plans for production rolling.

As for production, the parts would be cast at their usual foundry, located over the border in Canada. Both to save costs and to maintain control over the geometry, Kevin and his colleagues decided to produce the original patterns for the castings for later shipment to the foundry. They decided to have each pattern machined out of aluminum. One of the key decisions Kevin had to make involved the shrinkage allowance. The direction and uniformity of shrinkage in a casting often depends on the geometry and part features, though in this case he decided they could use a linear shrink rate in all directions.

Kevin’s last task for the new parts was to get an estimate of production cost. For the casting, Kevin consulted the foundry and they told him that the cost mainly depended on two quantities: the heat energy (and thus time) needed to melt the material for each part and the cycle time needed for solidification of each part in the mold. For the first part design, Kevin computed a 3.5 minute melting time based on the heat properties of steel and a 1000 kW electric-arc furnace which operates at 80% efficiency (i.e, 20% of the heat energy from the furnace is lost to the environment). Solidification trials on a simple 2-inch diameter, 4-inch long cylinder took 4.0 minutes, so Kevin calculated a 16 minute time for solidification of his first part based on its volume and surface area.

Question 1

GO TO THE TEXT: Chapter 10 (Groover/Introduction to Manufacturing Processes)

a) What are “no-bake” molds, and how do they compare to green sand molds? How are the expanded polystyrene foam patterns made for the lost foam casting process?

b) Which sand casting defects are due to the release of gases or from moisture in the sand molds?

c) Why is steel so much harder to cast than cast iron?

d) What typical tolerances can Kevin and his colleagues expect out of the sand casting process on their large, steel parts?

e) Although Section 10.3.3 in the textbook shows a more complicated picture of shrinkage, it is still common for practical casting operations to assume a consistent linear shrink rate. If Kevin’s part design calls for a length of 38 mm and a width of 22 mm, calculate the length and width for the pattern to accommodate a linear shrinkage value of 1.8%.

f) Use values from Table 4.1 and 4.2 and equation 10.1 to estimate the part volume corresponding to Kevin’s computation of 3.5 minutes for melting time. Assume the specific heat of the liquid metal steel is 20% smaller than that of the solid, and the heat of fusion is 120 J/g.   The steel melts at 1530ºC and is to be poured at 100ºC higher.

g) Use the part volume from Question 11 and the Solidification time method in Section 10.3.2 (with the results of Kevin’s solidification trials) to estimate the surface area for Kevin’s part corresponding to his 16-minute calculation.

Answer must be typed and presented clearly..

In: Mechanical Engineering

Engineers makes the quality of life easy, discuss.

Engineers makes the quality of life easy, discuss.

In: Mechanical Engineering

Assess the relevance of Mechanical Engineering discipline going by the new technological trends.

Assess the relevance of Mechanical Engineering discipline going by the new technological trends.

In: Mechanical Engineering

explain in details why is it not possible to have 100% safety in case of disaster.

explain in details why is it not possible to have 100% safety in case of disaster.

In: Mechanical Engineering

Hello. My question is what is the equation of magnetic attraction force to iron? How it...

Hello. My question is what is the equation of magnetic attraction force to iron? How it will lead to that equation?

In: Mechanical Engineering

Explain the function of various parts of a data acquisition system. What are the industrial applications...

Explain the function of various parts of a data acquisition system. What are the industrial applications of PC-based data acquisition system? and how it assists in calibration and testing of measurement sensors?

In: Mechanical Engineering

Hybrid Additive manufacturing is a process in which we use subtractive and additive processes together to...

Hybrid Additive manufacturing is a process in which we use subtractive and additive processes together to produce a part. Explain how this process can beat AM in terms of part quality.

In: Mechanical Engineering

Why is there a difference between the microstructure and properties of the metallic parts fabricated by...

Why is there a difference between the microstructure and properties of the metallic parts fabricated by AM compared to conventional processes?

In: Mechanical Engineering

A steam power plant with boiler use coal fuel with net heat 4000 kcal/kg and boiler...

A steam power plant with boiler use coal fuel with net heat 4000 kcal/kg and boiler efficiency 90%. If steam utrbine from the power plsnt generate power output 100 MW, at condition vapor enter at 10 MPa, 520oC and condensate to saturated liquid at 0.08 bar. If the isentropic efficiency turbine and pump is 90%, then

a) Calculate coal required (ton/hour)

b) Calculate netto efficiency of the power plant

c) Calculate Net Plant Heat Rate (kCal/kWh)

In: Mechanical Engineering

A cylindrical specimen of aluminum having a diameter of 0.75 inches and a length of 8...

A cylindrical specimen of aluminum having a diameter of 0.75 inches and a length of 8 inches is deformed elastically in tension with a force of 11,000 lb. Assume the following properties: Modulus of Elasticity: 10 Mpsi; Yield Strength: 40 kpsi; Tensile Strenght: 50 kpsi; Percent Elongation: 17; Poisson's Ratio: .33 Determine the following: (a) The amount by which this specimen will elongate in the direction of the applied stress (b) The change in diameter of the specimen. Will the diameter increase or decrease?

In: Mechanical Engineering