Ferrous and Non Ferrous Metals | Interview Question and answers

Ferrous and Non Ferrous Metals | Interview , viva, Oral Question and answers

1. What are metals? Classify engineering materials.

金属是元素物质。金属由易于放弃电子提供金属键和电导率的元件组成。
Types of metals: 1. Ferrous metals, and 2. Non-ferrous metals.

2. What are ferrous metals? Classify ferrous materials.

The metals, which contain iron as their main constituent, are called ferrous metals.
黑色金属类型：1.钢材和2.铸铁。

3. State three reasons why ferrous alloys are used extensively.

1. Iron-based components are relatively abundant and are widely distributed throughout the world.
含铁材料可以非常经济地生产。
3.黑色材料是多功能的。因此，可以实现多种机械和物理性质的含铁物质。

4. State three characteristics of ferrous alloys that limit their utilization.

重量重，电气和导热性较低，耐腐蚀性较低。

5. How can you specify a steel? What is the difference between 4140 steel and 4340 steel?

钢的AISI / SAE指定是四位数字：前两位数表示合金含量，最后两位数表示碳浓度。
4140钢是Cr-Mo的合金，具有0.40％C，其中4340钢是Mo-Cr-Ni的合金，0.40％C.

6. What are three primary groups of plain carbon steels?

1. Low-carbon steels:Those contain less than 0.25% carbon.
2. Medium-carbon steels:Those containing between 0.25 and 0.60% carbon.
3. High-carbon steels:Those containing more than 0.60% carbon.

7. What are alloy steels? How are alloy steels classified?

Alloy steels mean may steels other than carbon steels.
Alloy steels can be divided into two main groups as:
1. Low alloy steels:These contain up to 3 to 4% of alloying elements.
2.高合金钢：These contain more than 5% of alloying elements.

8. List four important alloying elements added in alloy steels.

最常用的合金元素是铬，镍，钼，钒，钨，钴，硼，铜等。

9. Why is alloying done?

The alloying steel is generally done:

To increase its strength.
To improve hardness.
提高韧性。
To improve resistance to abrasion and water.
To improve machinability.
To improve ductility.

10. What are the primary effects of chromium, and copper as alloying elements in steel?

Effects of alloying chromium:Increases corrosion and oxidation resistance, increases hardenability, increases high-temperature strength, and resists abrasion and wear (with high carbon).
Effects of alloying copper:Increases strength, and increases corrosion resistance.

11. What are the effects of lead and sulphur on the machinability of steels?

Lead improves the machinability whereas sulphur reduces it.

12. Which alloy elements are basically a) carbide formers, and b) graphite promoters?

a) Carbide formers:Cr, W, Ti, Mo, Nb, V, and Mn.
b) Graphite promoter:Si, Co, Al, and Ni.

13. What makes a stainless steel “stainless”?

氧化铬（非常致密的薄）保护层用作延迟进一步氧化，锈蚀或腐蚀的屏障。由于这种钢材不能轻易染色，因此它被称为不锈钢。

14. Why do stainless steels lose their corrosion resistance when the chromium in solution drops below 12%?

当铬的重量％低于12％时，腐蚀速率急剧增加。随着腐蚀速率的增加，所得铬氧化铬保护层有效地延缓氧化，锈蚀或腐蚀。

15. What determines whether a stainless steel is austenitic ferritic, or martenistic?

The predominant phase constituent of the microstructure present in a stainless steel determines whether a stainless steel is austenitic, ferritic, or martenistic.

16. What are the required properties of a tool steel?

Tool steels should have the following requirements:
1. Good toughness,
2.耐磨性好，
3. Very good machinability,
4. Slight change of form during hardening,
5. Little risk of cracking during hardening.
6. Resistance to softening on heating.

17. How can you classify tool steels?

1. Cold work tool steels,
2. Shock resisting tool steels,
3. Hot work tool steels,
4. High speed tool steels,
5. Plastic mold tool steels and
6. Special purpose tool steels.

18. What is meant by 18-4-1 high speed steel?

A widely used high-speed tool steel is 18-4-1 high speed steel. This steel contains 18% tungsten, 4% chromium, and 1% vanadium. It is considered to be one of the best of all purpose tol steels.

19. What are HSLA steels? Where are they used?

HSLA steels are nothing but high-strength low-alloy steels. HSLA steels, also known as micro alloyed steels, are low-carbon steels containing small amounts of alloying elements.
这些HSLA钢被广泛用作结构或结构合金钢。

20. What are maraging steels? Give its composition.

Maraging steels are low-carbon, highly alloyed steels. These are very high- strength materials that can be hardened to obtain tensile strengths of up to 1900 Mpa.
Composition:Masraging Steels含有18％的镍，7％钴和少量其他元素，如钛。碳含量低，一般小于0.05％。

21.耐热钢和自由加工钢材是什么？

Steels which can resist the creep and oxidation at high temperatures and retain sufficient strength are called heat resisting steels.
自由加工钢，也称为自由切削钢，机器容易和形成小芯片，以减少摩擦刀具和相关的摩擦和磨损。

22. What are the features that make cast iron an important material?

1. It is a cheap metallurgical substance,
2. Good castability,
3.良好的机械刚度和压缩下的良好强度。
4. Good machinability cn achieved when a suitable composition is selected.

23.碳对铸铁性能的影响是什么？

If a cast iron contains more of the brittle cementite, then its mechanical properties will be poor.

24.冷却率对铸铁性质的影响是什么？

High rate of cooling results in a weak and brittle cast iron. Slow cooling rate results in tough and strong cast iron.

25.什么是灰铸铁的化学成分？下面给出灰铸铁的典型组成：

碳 - 2.5至4％。
Silicon – 1 to 3%. Manganese – o.4 to 1%. Phosphorus – 0.15 to 1%.
硫磺 - 0.02至0.15％。剩下的是铁。

26.使用白铸铁在哪里？

1. White cast iron is used as a raw material in the production of malleable cast iron.
2. The typical applications of white cast irons include rolls, wear plates, pump linings, balls, etc.
3. It is also used for inferior casting and in places where hard coating is required as in the outer surface of car wheels.

28.延展铸铁和延性铸铁有什么区别？

Malleable cast iron is produced by heat treating unalloyed white iron. The ductile (or SG or nodular) cast iron is produced by adding magnesium and/or cerium to molten cast iron.
Both malleable and ductile cast irons have the nodules, also called spheroids. But the nodules of ductile cast irons are more perfect spheres.

29.合金铸造熨斗是什么？

The alloy cast irons, like alloy stels, can be produced by adding alloying elements like Ni, Cr, Mo, Cu, Si, and Mn.
已生产合金铸铁，以提供高强度材料，耐磨材料，耐腐蚀的铁杆和用于高温服务的铁杆。

30.列出铜和一些典型应用的出色属性。

The copper posses the following properties:
1. Copper possess very high electrical conductivity.
2. It also has very high thermal conductivity.
3. It exhibits excellent resistance to corrosion.
4. It is very soft, ductile and malleable.

Copper is extensively used for manufacturing power cables, telephone cables, cables for computer networks, printed circuit boards, connectors, etc.

31. What is the main difference between a brass and a bronze?

Brass is an alloy of copper and zinc whereas bronze is an alloy of copper and tin.

32. List at least four types of brasses used.

Gliding metal (or commercial bronze), cartridge brass, standard brass (or cold working brass), Muntz metal (or yellow metal), Naval brass, Admiralty brass.

33. List some bronze alloys.

Bell bronze, phosphor bronze, aluminium bronze, silicon bronze, coinage bronze and leaded bronze.

34.什么是枪支金属？给它的构成。

Gun metals are alloys of copper, tin, and zinc.
Composition of admiralty gun metal: 88 Cu, 10 Sn, 2 Zn, 2 (max) Ni.

35. What are cupronickels? What is the use of monel metal?

Cupronickels are alloys of copper and nickel.
Uses of monel metal: For making propellers, pump fittings, condenser tubes, steam turbine blades, sea water exposed parts, tanks, and chemical and food handling plants.

36. What properties have made aluminium and its alloys the most important non-ferrous metal?

i) Light-weight (one-third the weight of steel),
ii) High thermal and electrical conductivity,
iii) Excellent corrosion resistance,
iv) Non-toxicity,
v) Soft and ductile,
vi) Low specific gravity,
vii) High strength-to-weight ratio, and
viii) High reflectivity.

37. Why does the aluminium replace the copper as an electrical conductor?

i) The price of the aluminium is much lower than that of copper.
ii) The specific gravity of aluminium.
iii) The electrical conductivity of EC-grade (electrical conductor) aluminium is 61% of the conductivity of standard copper, based on equal cross sections.
iv) If equal weights of aluminium and copper conductors of a given length are compared, it is found that aluminium conducts 201% as much current as does copper.

38. What are the two types of aluminium alloys?

1. Heat-treatable aluminium alloys, and
2. Non-heat treatable aluminium alloys.