Most Frequently asked questions in a Interview

Que-1: Tell us something about yourself ?

Que-2: What do you consider as your most significant professional / academic achievement? Why?

Que-3: Describe a challenging project or a seemingly impossible task which you’ve undertaken.

Que-4: At times, many of us are caught in a situation of moral conflict, where we have to choose between two seemingly right alternatives. Give us one situation when you faced this conflict. How did you resolve it?


Que-5: Sometimes, we may find a group of people disagreeing with our beliefs / point of view. Give us an instance where you had to convince a group of people on your point of view?

Que-6: Cite one instance where you had to compromise on your values?

Que-7: What were your three key focus areas during the last 3 years & your accomplishments in them?

Que-8: What are the types of assignments that keep you hooked and charged and what are those that you find boring?

Que-9: Describe an incident that had a deep impact on you and has brought about a significant change in you?

Que-10 What are your short term goals?

Que-11 What are your Long term goals?

Que-12 Where do you see yourself 5 years down the line?

Design & Process of Steel Bloom

Introduction

Steel is an alloy made by combining iron and other elements, the most common of these being carbon. When carbon is used, its content in the steel is between 0.2% and 2.1% by weight, depending on the grade. Other elements used are manganese, chromium, vanadium and tungsten. Carbon and other elements act as a hardening agent, preventing dislocations in the iron atom crystal lattice from sliding past one another. Varying the amount of alloying elements and the form of their presence in the steel (solute elements, precipitated phase) controls qualities such as the hardness, ductility, and tensile strength of the resulting steel. Steel with increased carbon content can be made harder and stronger than iron, but such steel is also less ductile than iron.

When iron is smelted from its ore by commercial processes, it contains more carbon than is desirable. To become steel, it must be melted and reprocessed to reduce the carbon to the correct amount, at which point other elements can be added. This liquid is then continuously cast into long slabs or cast into ingots. Approximately 96% of steel is continuously cast, while only 4% is produced as cast steel ingots. The ingots are then heated in a soaking pit and hot rolled into slabs, blooms, or billets. Slabs are hot or cold rolled into sheet metal or plates. Billets are hot or cold rolled into bars, rods, and wire. Blooms are hot or cold rolled into structural steel, such as I-beams and rails. In modern foundries these processes often occur in one assembly line, with ore coming in and finished steel coming out.

Design of Bloom

Different design principles are used for casting strands of different cross sections. Bloom casters solidify sections of 300 by 400 millimeters.

Steel Bloom dependable Semi-finished product for steel plant. The Steel Bloom is widely demanded in different size and dimension with different quality.

Sizes:

Different Sizes of Steel bloom like 200x200 Mm, 260x260 Mm, 260x340 Mm, 265x335 Mm.

Length:

Specifiable Up to 12 M

                 

Chemical Composition of Bloom

Grade	C	Mn	Si	S(Max)	P(Max)	Al(Max)	Mo(Max)	Cr	V(Max)
880	0.60-0.80	0.80-1.30	0.10-0.50	0.030*	0.030*	0.015	-	-	-
1080 Cr	0.60-0.80	0.80-1.20	0.50-1.10	0.025	0.025	0.004	0.20	0.80-1.20	0.20
VANADIUM (VN)	0.60-0.80	0.80-1.30	0.10-0.50	0.025*	0.030*	0.015	-	-	0.20
Copper-Molybdenum (CM) 0.35	0.60-0.80	0.80-1.30	0.10-0.50	0.030*	0.030*	0.015	0.2-0.3	-	0.25

Mechanical properties of Bloom Steel

UTS(MPa)(min)	Yield Strength***(MPa)(min)	Elongation% om Gauge Length-5.65 So(min)
880	460	10.0
1080	560	9.0
880	540	10.0
880	460	10.0

Uses of Steel Bloom

Wire rod

Railway rails

 

TMT rod etc

Process of Steel Making

1.     Molten pig iron (sometimes referred to as "hot metal") from a blast furnace is poured into a large refractory-lined container called a ladle;

2.     The metal in the ladle is sent directly for basic oxygen steelmaking or to a pretreatment stage. Pretreatment of the blast furnace metal is used to reduce the refining load of sulfur, silicon, and phosphorus. In desulfurising pretreatment, a lance is lowered into the molten iron in the ladle. The decision to pretreat depends on the quality of the blast furnace metal and the required final quality of the BOS steel

3.     Filling the furnace with the ingredients is called charging. The BOS process is autogenous: the required thermal energy is produced during the process.

4.     The vessel is then set upright and a water-cooled lance is lowered down into it. The lance blows 99% pure oxygen onto the steel and iron, igniting the carbon dissolved in the steel and burning it to form carbon monoxide and carbon dioxide, causing the temperature to rise to about 1700°C.

5.     Fluxes (burnt lime or dolomite) are fed into the vessel to form slag, which absorbs impurities of the steelmaking process. During blowing the metal in the vessel forms an emulsion with the slag, facilitating the refining process.

6.     The BOS vessel is tilted again and the steel is poured into a giant ladle. This process is called tapping the steel. The steel is further refined in the ladle furnace, by adding alloying materials to give the steel special properties

                              Flow diagram of Steel Making

Process of Steel Bloom

Molten steel is cast into large blocks called "blooms". During the casting process various methods are used, such as addition of aluminum, so that impurities in the steel float to the surface where they can be cut off the finished bloom.

Because of the energy cost and structural stress associated with heating and cooling a blast furnace, typically these primary steelmaking vessels will operate on a continuous production campaign of several years duration. Even during periods of low steel demand, it may not be feasible to let the blast furnace grow cold, though some adjustment of the production rate is possible.

Integrated mills are large facilities that are typically only economical to build in 2,000,000 ton per year annual capacity and up. Final products made by an integrated plant are usually large structural sections, heavy plate, strip, wire rod, railway rails, and occasionally long products such as bars and pipe.

Steel Bloom produce by Continuous Casting

In this process, molten steel flows from a ladle, through a tundish into the mold. The tundish holds enough metal to provide a continuous flow to the mold, even during an exchange of ladles, which are supplied periodically from the steelmaking process. The tundish can also serve as a refining vessel to float out detrimental inclusions into the slag layer.

Once in the mold, the molten steel freezes against the water-cooled walls of a bottomless copper mold to form a solid shell. The mold is oscillated vertically in order to discourage sticking of the shell to the mold walls. Drive rolls lower in the machine continuously withdraw the shell from the mold at a rate or “casting speed” that matches the flow of incoming metal, so the process ideally runs in steady state. The liquid flow rate is controlled by restricting the opening in the nozzle according to the signal fed back from a level sensor in the mold.

                    

Test of Steel Bloom

Nondestructive testing or Non-destructive testing (NDT) is a wide group of analysis techniques used in science and industry to evaluate the properties of a material, component or system without causing damage. The terms Nondestructive examination (NDE), Nondestructive inspection (NDI), and Nondestructive evaluation (NDE) are also commonly used to describe this technology. Because NDT does not permanently alter the article being inspected, it is a highly-valuable technique that can save both money and time in product evaluation, troubleshooting, and research. Common NDT methods include ultrasonic, magnetic-particle, liquid penetrant, radiographic, remote visual inspection (RVI), eddy-current testing.

In ultrasonic testing (UT), very short ultrasonic pulse-waves with center frequencies ranging from 0.1-15 MHz and occasionally up to 50 MHz are launched into materials to detect internal flaws or to characterize materials. In ultrasonic testing, an ultrasound transducer connected to a diagnostic machine is passed over the object being inspected. The transducer is typically separated from the test object by a couplant (such as oil) or by water, as in immersion testing.

Advantages

1.     High penetrating power, which allows the detection of flaws deep in the part.

2.     High sensitivity, permitting the detection of extremely small flaws.

3.     Only one surface need be accessible.

4.     Greater accuracy than other nondestructive methods in determining the depth of internal flaws and the thickness of parts with parallel surfaces.

5.     Some capability of estimating the size, orientation, shape and nature of defects.

design-process-of-steel-boom
6.     Nonhazardous to operations or to nearby personnel and has no effect on equipment and materials in the vicinity.

7.     Capable of portable or highly automated operation

Summary of "Looking beyond the obvious: Unraveling the Toyota production system"

Looking beyond the obvious: Unraveling the Toyota production system                         

Introduction

The Toyota Production System (TPS) is an integrated socio-technical system, developed by Toyota that comprises its management philosophy and practices. The Toyota Production System TPS has attracted the attention of many firms, but few have been able to achieve success to the level enjoyed by Toyota. The TPS organizes manufacturing and logistics for the automobile manufacturer, including interaction with suppliers and customers. The main objectives of the TPS are to design out overburden and inconsistency and to eliminate waste. The most significant effects on process value delivery are achieved by designing a process capable of delivering the required results smoothly; by designing out inconsistency. It is also crucial to ensure that the process is as flexible as necessary without stress or overburden since this generates waste. Finally the tactical improvements of waste reduction or the elimination of waste are very valuable. Toyota was able to greatly reduce leadtime and cost using the TPS, while improving quality. This enabled it to become one of the ten largest companies in the world. It is currently as profitable as all the other car companies combined and became the largest car manufacturer in 2007. Due to the success of the production philosophy's predictions many of these methods have been copied by other manufacturing companies, although mostly unsuccessfully.

Objective:

(1) To study the main effects of TPS as a set of practices on cycle time, quality, cost, and delivery dimensions of manufacturing performance

(2) To study the main effects of TPS as a set of rules underlying problem solving techniques on cycle time, quality, cost, and delivery dimensions of manufacturing performance and

(3) To study the interaction effects of TPS as a set of practices and as a set of rules on cycle time, quality, cost, and delivery dimensions of manufacturing performance.

Major Themes in TPS rules and TPS practices

In TPS both internal and external links are connected to understand the entire system Specifically the objective is to detect, assess and eliminate sources of variation in the entire system. The design of sequential relationship among internal and external links involves three types of integration: upstream integration, i.e. between the external suppliers and the internal suppliers within the firm ;internal integration, between actors within the firm that own successive process stages as either internal supplier so both internal suppliers and internal customers; and downstream integration, between the internal suppliers that own the very last process stage and the firm’s external customers.

Hypotheses

Hypotheses (H1). TPS practices have a direct and positive effect on manufacturing cycle time, quality, cost, and deli very performance.

Hypotheses (H2). TPS rules have a direct and positive effect on manufacturing cycle time, quality, cost, and delivery performance.

Hypotheses (H3). TPS practices and TPS rules have an interactive and positive effect on manufacturing cycle time, quality, cost, and delivery performance.

Sampling

Belonging to industries classified in SIC34-Fabricated Metal Products (except Machinery and Transportation Equipment);SIC 35—Industrial and Commercial Machinery and Computing Equipment; SIC36—Electronic another Electrical Equipment and Components; SIC37—Transportation Machinery and Items; and SIC 38—Measuring, Analyzing and Controlling Instruments, Photographic, Medical and Optical Goods. Firm sin these SICs (together with SIC39) account for over 40% of U.S. manufacturing sales, and are establish users of advanced manufacturing systems in discrete product manufacturing (U.S. Department of Commerce, 1988; Snell and Dean, 1992). Since it measures are related to both purchasing and manufacturing, a multiple respondent approach for the entire sampling frame would have been ideal. However, this approaches as well-known empirical constraints, including prohibitive time, cost, and response rate constraints (Kumar etal., 1993). ). The respondent in their study was the director of materials, materials manager or equivalent senior executive at the plant or SBU level. High-ranking respondents tend to be more reliable sources of information than their subordinate ranks

Measurement

The Toyota Production System has well recognized practices, such as Kanban, preventive maintenance, set-up time reduction, group technology, in-plant communication systems, and JIT supplies. TPSrules,The responses of most respondents were benchmarked against the use of practices and rules over the past three years, ranging from a very low to a very high extent of actual use on a 1–5 Likert scale. Manufacturing performance was operationalized to include the conventional dimensions of manufacturingcycle time reduction, quality improvement (conformance), cost reduction, and delivery speed. For each item, respondents were asked to provide a rating of their plant’s manufacturing performance relative to internal goals and relative to the performance of key competitors.

Data Analysis and Results

Hierarchical regression analysis was used to examine the hypotheses. They conducted a series of separate regression runs for each of the four dimensions of manufacturing performance. Product life cycle stage, firm size (as measured by number of employees), and cost of delay in meeting customer orders (market velocity) were included as control variables.

Main TPS practices and TPS rules effects

The First hypothesis (H1) Proposes that TPS practices have a direct effect on manufacturing cycle time, quality, cost, and delivery performance. The results provide some support for H1, as several TPS practices including production schedule information sharing with supplier, Kanban, in-plant EDI, use of set-up reduction techniques, and JIT supplier delivery, showed significant main effects on multiple aspects of manufacturing performance.

The Second hypothesis (H2) Proposes that TPS rules have a direct effect on manufacturing cycle time, quality, cost, and delivery performance. The findings were mixed. For instance, joint problem solving with suppliers and the use of cross trained employees had strong significant positive effects on cost reduction performance. Worker cross training and the use of manufacturer operator teams had positive effects on cost reduction and manufacturing cycle time reduction, respectively. Unanticipated relationships were also observed. Direct communication between buyer and supplier production schedulers had significant negative effects on both quality performance and cost reduction.

The Third hypothesis (H3) Proposes that TPS practices and TPS rules have interactive effects on manufacturing cycle time, quality, cost, and delivery performance. The interactions modeled between TPS practices and TPS rules revealed several joint effects on the various performance measures.

Preventive maintenance, another TPS practice, had mixed effects. Its inter-action with the TPS rule of using operator teams had significant negative effects on quality performance and cost reduction. However, the same practice significantly improved manufacturing cycle reduction, quality, cost reduction, and delivery speed performance when combined with the TPS rule of using decentralized decision making for micro production scheduling. The use of set-up time reduction techniques, another TPS practice, had a strong positive impact on quality performance and cost reduction, when combined with the TPS rule of using operator teams. Yet, the same practice had a strong negative effect on cost reduction performance. JIT supplier deliveries significantly improved delivery speed performance in the presence of the rule of joint problem solving with suppliers (weak significance for manufacturing cycle time). Interestingly, JIT supplier deliveries significantly impaired manufacturing cycle time reduction and delivery speed performance in the presence of direct communication between production schedulers at buyer and supplier plants.

Discussion and Implication

Effects of TPS practices and TPS rules:

The results for four TPS practices conformed to expectations, i.e. use of in-plant EDI, Kanban, use of set-up time reduction techniques, and JIT supplier delivery were associated with positive changes in manufacturing cycle time reduction, quality, cost reduction and delivery speed performance. Surprisingly, the TPS practice of production schedule information sharing with suppliers had a significant and negative impact on manufacturing cycle time, cost reduction, and delivery speed performance. Another TPS rule, the use of decentralized decision making for micro production scheduling, also indicated negative direct effects on plant delivery speed performance. They conjecture that workers making local decisions about what and when to produce may not have full access to, or a complete understanding of plant level requirements and constraints, possibly leading to conflicts in scheduling rules and priorities at the level of the plant. Although it might seem that in some contexts the decentralization of decision making for micro production is a necessary evil, this pattern might not hold true in other contexts

Interaction effects between TPS practices and TPS rules:

The interactions provide interesting insights. Using suppliers with volume flexibility capabilities did not combine well with the use of joint problem solving with such suppliers. They speculate that volume flexibility may well increase supplier production costs, if activated too frequently or for extreme swings in volume.

The use of set-up time reduction techniques, a TPS practice with positive direct effects on plant performance, appears counter-productive in the presence of worker cross training or decentralized decision making for operator daily task distribution. Set-up time reduction initiatives are typically equipment centered team kaizen events, with inputs from different experts. Worker cross training, an independently beneficial rule, may actually deter the development of such machine level expertise. Cross training may have the disadvantage of diluting or preventing the acquisition of deep knowledge and expertise in a specific production machine. set-up time reduction events demand team work, focusing multiple sources of specific expertise, to a particular work objective. The positive effects of using set-up time reduction techniques in combination with manufacturer operator teams corroborate this perspective.

Implication

TPS should be approached with caution piece meal or indiscriminate adoption of TPS practices or rules may be dangerous. Indeed, certain combinations of rules and practices may be detrimental to performance. Carefully calibrated, TPS would seem to potentially impact plant performance across the board, including cost, quality, manufacturing cycle time, and delivery performance.

Conclusion and Future Scope

They adopted an integrated perspective to include the rules underlying TPS; They proposed and found some support for the combinatorial power of TPS practices and TPS rules with regards to several manufacturing performance outcomes. In order to minimize explanatory complexities, they did not explore three-way interactions, providing thus an opportunity for future research that could look at such higher order interactions. Contrary to their expectations, the results indicated a few negative relationships which might need further clarification to confirm their pattern consistency. However, They also posit a caveat about the above discussed results

Reference:
Looking beyond the obvious: Unraveling the Toyota production system by: Jayanth Jayaram, Ajay Das and Mariana Nicolae, Int. J. Production Economics 128 (2010), 280-291