Material Knowledge Article

Material Knowledge Article

Below are some questions and answers related to material knowledge:

1. Low Carbon Steel Cutting Method:

• Question: What method is used to cut low carbon steel?

• Answer: Using O2 gas.

2. Chemical Structure:

• Question: Among the following structures, which is a chemical structure?

• Answer: Cementite

3. Purpose of Adding Modifiers in Metal Casting:

• Question: When casting metals, why is it common to add modifiers?

• Answer: To refine the crystal grain size.

4. Main Target of Common Hot-Rolled Steel:

• Question: What is the main target of common hot-rolled steel?

• Answer: Good mechanical properties (CTM)

5. Hardness Symbol:

• Question: Which symbol below indicates hardness?

• Answer: HB (Brinell Hardness)

6. Factor Causing Shear Deformation:

• Question: Which factor causes shear deformation during the sliding process?

• Answer: Tangential stress on the sliding surface.

7. Steel Code according to TCVN 1766-75:

• Question: According to TCVN 1766-75: what is the percentage of C in the C45 steel grade?

• Answer: %C = 0.45

8. Aluminum with Highest Purity:

• Question: Choose the type of aluminum with the highest purity?

• Answer: A85

9. Non-Magnetic and Spark-Free Alloy:

• Question: Which of the following alloys is non-magnetic and does not spark when subjected to strong impacts or friction?

• Answer: Mg alloy (Magnesium)

10. Best Pouring Temperature Range for Steel Casting:

• Question: What is the best temperature range for pouring steel casting?

• Answer: 730 – 1147 degrees Celsius

11. Welding Method with Highest Temperature:

• Question: Which welding method generates the highest temperature in the welding zone?

• Answer: Gas welding

12. Machining Method for Producing Fiber-Shaped Products:

• Question: Which machining method produces fiber-shaped products?

• Answer: Drawing

13. Shielding Gas in MAG Welding:

• Question: Which of the following welding methods uses the shielding gas (80%Ar + 20%CO2)?

• Answer: MAG welding (Metal Active Gas)

14. 1-Carbides Hardmetal:

• Question: Which one is a 1-carbide hardmetal?

• Answer: Bk8

15. Carbon Content of 10Cr13 Steel:

• Question: Indicate the carbon content of 10Cr13 steel?

• Answer: 0.1%C

16. Factor not Affecting the Fluidity of Casting Alloys:

• Question: Which of the following factors does not directly affect the fluidity of casting alloys?

• Answer: Density

17. Factor Representing the Ease of Pressure Processing of Material:

• Question: Which of the following factors indicates the ease of pressure processing of a material?

• Answer: Ease of rolling

18. Symbol of Highest Surface Finish:

• Question: Which symbol below indicates the highest surface finish?

• Answer: RZ60

19. Material with Highest Strength:

• Question: Which of the following materials has the highest strength?

• Answer: GC 45-5

20. Purpose of Cyanidation:

• Question: What is the most accurate purpose of cyanidation?

• Answer: To increase hardness and corrosion resistance

21. Criterion not Related to the Castability of Casting Alloys:

• Question: Which of the following criteria is not related to the castability of casting alloys?

• Answer: Heat resistance

22. Electrode Used in MIG Welding:

• Question: Indicate which type of electrode is used for MIG welding?

• Answer: Flux-cored welding wire

23. Symbol for Cutting Length on the (hv) Diagram:

• Question: On the (hv) diagram, indicate the symbol for cutting length?

• Answer: S

24. Element that Most Strongly Increases the Hot Shortness of Steel:

• Question: Which of the following elements most strongly increases the hot shortness of steel?

• Answer: S (Sulfur)

25. Transmission in the Dividing Head:

• Question: Indicate the transmission used in the dividing head?

• Answer: Screw – Worm gear

26. Welding Method Using Filler Metal with Melting Point < 450^oC:

• Question: Which welding method uses filler metal with a melting point < 450^oC and different from the weld material?

• Answer: Patch welding (only applicable for repair, patching damaged areas of the material, low temperature)

27. Welding Method Achieving High Impact Toughness:

• Question: Among the following methods, which one achieves high impact toughness?

• Answer: Tempering in two environments

28. Existence of Fe in the Temperature Range of 911 – 1392 degrees Celsius:

• Question: In the temperature range of 911 – 1392 degrees Celsius, what is the form of Fe?

• Answer: Fe γ (Austenite) non-magnetic