Mechanical Engineering Concepts

Mechanical Engineering

• Gases commonly used in tungsten arc welding include helium and argon.
• Linde welding employs a neutral flame and leftward technique.
• Welding of glass is performed using electron beam welding.
• Cold chisels are crafted through forging.
• Extrusion is extensively used to manufacture bolts and nuts.
• Structural components like rails, angles, and I-beams are produced through hot rolling.
• In die casting, machining allowance isn't provided.
• Cohesiveness is the property of sand that allows sand grains to stick together.
• A casting defect appearing as rough lumps near the ingates on a casting's surface is known as scab.
• The symbol used for butt resistance weld is V.
• The radius of the chamber arc for the bolt nominal diameter of D in bolted joints is 1.5D.
• Elongation of more than 15% indicates that a material is ductile.
• The property of a material to be twisted, bent, or stretched under high stress before rupture is known as toughness.
• Shock resistance of steel is increased by adding nickel and chromium.
• Alloy steels and high-speed steels are heated to 1100 to 1300°C for hardening.
• Normalizing is a heat treatment process used for castings.
• The percentage of phosphorus in phosphor bronze is 1.
• In powder metallurgy, pressures range from 690 to 13750 bar to compress powdered metals in desired proportions in molds.
• The angles between two forces for minimum and maximum resultants are 180° and 0°, respectively.
• Poisson's ratio for cast iron varies from 0.23 to 0.27.
• Point of contraflexure occurs in overhanging beams.
• For a simply supported beam A with length I, breadth b, and depth d supporting a central load W, another beam B of same dimensions with a 2W load results in deflection of beam B being half that of A.
• The strain energy stored in a spring under maximum load without permanent distortion is referred to as proof resilience.
• With a flat belt drive where slip between driver and belt is 1%, between belt and follower is 3%, and equal pulley diameters, the drive's velocity ratio is 0.96.
• Inventory model is a transportation technique belongs to one of the mathematical models in operations research.
• Tilting front wheels away from vertical, viewed from the car's front, is called camber.
• The starter motor is driven by the gear drive.
• Parking brake generally acts on rear wheels.
• Gear shift lever requires two motions to shift gears, first selects the synchronizer.
• The maximum torque multiplication ratio in a torque converter is about 2.5.
• Two-speed reverse gear arrangement is generally present in case of trucks.
• Tie-rod connects the steering rack to the knuckles.
• Blanking describes cutting a flat sheet into a desired shape.
• A hacksaw blade is specified by its length.
• Accuracy of micrometers, calipers, and dial indicators can be checked by using a slip gauge.
• Sine bar is specified by the centre to centre distance between the rollers.
• Rebating in carpentry involves making a recess on the edge of a workpiece.
• Continuous chips with a built-up edge form during the machining of ductile metals.
• Tumbler gears in a lathe provide the desired direction of movement to the lathe carriage.
• In a radial drilling machine, the work is usually rotated while the drill is fed.
• The amount of thickness metal removed in lapping operation is 0.05 0.1 mm.
• Planetary milling machine enables Internal or external threads of different pitche can be produced .
• Burnishing is a gear finishing operation.
• FMS is suited for low volume, high variety, intermittent flow products.
• CNC drilling machine is considered to be Adaptive controlled machine
• Seam welding is best for metal thickness ranging from 3 to 5mm.
• In submerged arc welding, the arc is produced between a bare metal electrode and the work.
• Hydraulic efficiency of an impulse turbine maximum when velocity of wheel is half of the jet velocity
• Speed ratio in case of Francis turbine varies from 0.15 to 0.3.
• The regulating valve provided on the casing of a centrifugal pump.
• In a reciprocating pump, air vessels are used to reduce acceleration head.
• Hydraulic torque converter is used for varying or increasing/decreasing the torque to the driven shaft.
• The best suited boiler for fluctuating steam demand is the Locomotive boiler.
• Effective stress in wire ropes during normal working is the combined axial load plus acceleration or retardation stresses.
• The centrifugal tension in the belt has no effect on the power transmitted.
• In roller chain the roller diameter is approximately 5/8 of the pitch.
• Spiral spring is used in mechanical wrist watch.
• The arrangement where two non-intersecting, non-coplanar shafts are connected by gears is known as spiral gearing.
• The cam follower extensively used in aircraft engines is roller follower.
• The ratio of circumferential stress to longitudinal stress in a thin cylinder subjected to an internal pressure is 2.
• Under bending moment M and torque T, where maximum bending stress equals maximum shear stress developed, M is equal to 2T.
• Forces are assumed to be uniformly distributed along the length of a key in design.
• Sleeve or muff coupling is designed as a thick cylinder.
• Charles' Law states that all perfect gases change in volume by 1/273 of their original volume per 1°C change in temperature, at constant pressure.
• Isentropic process means reversible adiabatic process.
• The hyperbolic law is governed by Boyle’s law.
• A thermodynamic cycle consisting of two constant pressure and two isentropic processes is known as joule cycle.
• Alpha-methyl-naphthalene has a cetane number of 0.
• The inlet valve of a four-stroke cycle combustion engine remains open for 230°.