Partial fulfillment of the requirement for the degree of MASTER OF TECHNOLOGY. Mechanical Engineering) [Specialization: Production Engineering]. This is to confirm that the thesis entitled "MECHANICAL AND MECHANICAL PROPERTIES OF CARBURETED MILD STEEL SAMPLES" submitted by Mr. K Sahoo, Head of the Department of Mechanical Engineering, NIT, Rourkela for providing me the necessary facilities in the department.
I would also like to thank all the colleagues of the Department of Mechanical Engineering and Metallurgical Materials Engineering for their inspiration and help. In this research, the mechanical and wear behavior of mild steels carburized at different temperature ranges of 850, 900 and 950 °C were studied and it was found that a simple heat treatment greatly improves the hardness, tensile strength and wear resistance of mild steels. The objective was to study the effects of these different temperatures and carburizing conditions on the mechanical and wear properties of carburized mild steels.
The results of this experiment show that the carburizing process greatly improves the mechanical and wear properties such as hardness, tensile strength and wear resistance, and these properties increase with the increase of the carburizing temperature, but in addition the resistance property decreases and further decreases. with increasing carburization temperature. The experimental results also show that mild steels carburized under different temperature ranges as stated above, with which mild steels carburized at 9500C give the best results for different types of mechanical and wear properties, because in this temperature gives the highest. tensile strength, hardness and wear resistance, so it should be preferred for demanding applications.
INTRODUCTION
- An overview :-
- Need of present work :-
- Ferrous materials :-
- Steels: - Carbon contain up to 2%
- Cast iron: - Carbon contain above 2% to 6.67%
- Plain carbon steels :-
- Low carbon steel: - up to 0.30% of carbon
- Medium carbon steel: - From 0.30 to 0.60% of carbon
- High carbon steel:- From 0.60 to 1.70% of carbon
- Case hardening :-
- Types of case hardening :-
- Tempering:-
- Wear of material:-
- Mechanical properties:-
- Objectives of the present work:-
- Abrasive wear 2. Toughness
- LITERATURE REVIEW LITERATURE REVIEW
- EXPERIMETAL DETAILS
Carbon is added to the outer surface of the steel, to a depth of approximately 0.03 mm. This hardening process includes a wide variety of techniques used to improve the mechanical properties and wear resistance of parts without affecting the softer, harder interior of the part. If this gas is not supplied, large non-uniformity is likely to occur if the depth above the surface of the part is likely.
Vacuum carburizing and plasma carburizing have found applications due to the absence of oxygen in the furnace atmosphere. Carbonitriding is a modified form of gas carburizing, at a temperature range between C. The modification consists of introducing ammonia into the gas carburizing atmosphere to add nitrogen to the carburized case as it is produced. The induction heat only penetrates the outer surface of the workpiece, resulting in only the skin being hardened by the quenching process.
Tensile strength is a measure of resistance to tearing when placed under tensile stress. The objective of the present work is to improve the mechanical properties and wear resistance of mild steels using vasundhara coal as a carburizing agent and a less energy consuming carburizing technique. The hardness of the abrasives affected the applied loads and wear distances.
Khusid et al [9] in his work studied the Wear of carburized high chrome steel and reported that Carburization increases the abrasion resistance and enables significant suppression of the adhesion phenomena under dry sliding.
Materials and Methods )
- Materials Selection:-
- Preparation of test specimens:-
- Specimen for toughness test:- A toughness test specimen as per ASTM standard is prepared for the same purpose having the following dimensions
- Specimen for tensile strength test:- A tensile test specimen as per ASTM standard is prepared for this purpose is based on the following equation
- Proximate analysis of vasundhara coal:-
- Carburization of mild steel samples:-
- Abrasive wear test:-
- wear volume:-
- wear rate:- It is defined as wear volume per unit distance travelled Wear rate =wear volume / sliding distance(s)
- wear resistance:- wear resistance is a reciprocal of wear rate wear resistance = 1 / wear rate
- Hardness test:-
- Tensile test:-
- Toughness (Charpy impact) test:-
- Results of proximate analysis of Vasundhara coal:-
- Results of abrasive wear test:-The abrasion characteristics of carburized mild steels
- Effect of carburization temperature on weight loss of carburized mild steels:-
- Effect of load on the weight loss of carburized mild steels:-
- Effect of carburization temperature on wear resistance of carburized mild steels:-
- Effect of hardness on the weight loss of carburized mild steels:-
- Effect of carburization temperature on tensile strength of carburized mild steels:- mild steels:-
- Effect of carburization temperature on toughness of carburized mild steels:- steels:-
One gram of air-dried coal pulverized sample of size -72 root was taken in a borosil glass crucible and then kept in the air oven maintained at the temperature of 110°C. The sample was soaked at this temperature for one hour and then removed from the oven and cooled. One gram of air-dried carbon powder sample of size -72 was taken in a volatile matter crucible (made of silica) and kept in the muffle furnace maintained at the required temperature of 925°C. The sample was soaked at this temperature for seven minutes and then the crucible was removed from the oven and cooled in air. One gram air-dried powdered sample of size -72 mess was taken in a shallow silica disc and kept in the muffle furnace maintained at a temperature of 775-800°C. The sample was kept in the oven until complete firing.
From the experimental results of abrasive wear test (Table 3 – 5), the following regularities can be found. The weight loss during grinding is highest for uncarburized simple mild steel and is lowest for the mild steel carburized at a temperature of 9500C. The wear resistance is the highest for the mild steel carburized at the temperature of 9500C and it is the lowest for the uncarburized mild steel.
To take only the case of carburized mild steel, wear resistance is also highest for mild steel carburized at a temperature of 9500C and is lowest for mild steel carburized at a temperature of 8500C. From the results of the toughness test (Table – 7), it is analyzed that the toughness varies between the range of 54J – 32J, and it is highest for the uncarburized mild steels and lowest for the mild steels carburized at a temperature of 9500C. So it is concluded that the carburizing process reduces the toughness of mild steel.
The hardness values varied between the range of 51 Rc – 57 Rc and it is highest for mild steel carburized at a temperature of 9500C and is lowest for mild steel carburized at. From the graph it is shown that the weight loss curve decreases gradually with increase in carburizing temperature. This result is expected because as the carburizing temperature increases, the hardness of carburized mild steel also increases, and due to the increase in hardness, the weight loss due to wear decreases.
The effect of the carburizing temperature on the wear resistance of carburized mild steels for the three different temperatures of 850, 900 and 9500C is shown in Tables 3 – 5 and it is depicted graphically in Fig. 18 – 21. So the mild steel carburized at temperature of 9500C gives the best result and is preferred. The effect of carburizing temperature on the tensile strength of carburized mild steels is shown in Table – 8 and it is also represented graphically in Fig.26.
The mild steel, carburized at 950°C, therefore gives the best results and is therefore preferred. This shows that with an increase in carburizing temperature, the toughness of carburized mild steel decreases.
CONCLUSION AND SUGGESTIONS FOR FUTURE WORK
Conclusions:-
Suggestions for the future work:-
Weight loss Vs Temp
Weight loss vs Temp
Wear rate Vs Temp
Wear resistance vs Temp
Weight loss vs hardness
Weight loss vs Hardness at diff. loads
Tensile strength vs Temp
Toughness vs Temp
Hardness Vs Temp
Tensile strength vs Hardness
Wear resistance vs Hardness
Effects of Cr and Ni addition on the structure and properties of carburized low carbon steel, Trans. Corrosion inhibition of mild steel in hydrochloric acid by sodium lauryl sulfate, Journal of chemistry pp. Effect of carbonization and hydrogenation on the impact toughness of AISI 4118 steel, Surface and Coating Technology pp.
Corrosion Wear Behavior of Boronized Carbon and Low Alloy Steels, Journal of Material Processing Technology p. Relationship between Case Depth and Flexural Fatigue Strength of Gas Carburized SAE 8620 Steels, Surface and Coating Technology p. treatment, International Journal of Fatigue pp.
