None -. .is a technique by which bothsurface hardness and fatigue life areenhanced for steel alloys.O Case hardeningPrecipition HardeningO work hardening

case hardening is a method where we instill hardness on the surface while keeping the inside soft.…

Answered: -.. .is a technique by which both…

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-.. .is a technique by which both surface hardness and fatigue life are enhanced for steel alloys.

Precision Machining Technology (MindTap Course List)

2nd Edition

ISBN:9781285444543

Author:Peter J. Hoffman, Eric S. Hopewell, Brian Janes

Publisher:Peter J. Hoffman, Eric S. Hopewell, Brian Janes

Chapter2: Measurement, Materials, And Safety

Section2.7: Heat Treatment Of Metals

Problem 2RQ: Direct hardening can be performed on steel containing at least________ carbon.

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Q1: Austenitized 40 mm diameter 5140 alloy steel bar is quenched in agitated oil. Predict what is the Rockwell hardness of this bar will be at (a) its surface and (b) its center (c) What do you think about the difference in hardness number between the center and surface (d) Differentiate between hardness and hardenability (e) Rank the steels in the figure below from lowest to highest hardenability and explain why. 600- Bar diameter (mm) 100 80 60 40 20 0 300 0 Cooling rate at 700°C (°C/sec). -150 55 0 تنا 25 ------- 5 S 10 12.5 8 M-R L 1/2 34-R Agitated oil 15 20 ¼ ¾ Distance from quenched end. De (Jominy distance) 5,5 54 Car Bar diameter (in.) 0 25 mm. 1 in. Hardness (Rockwell C) Where (C = center, S = surface, M-R = mid-radius) 2828 292 65 60- 55- 50 45 40 35 30 25 20 15 10 0 J 10 5140 30 20 Distance from quenched end (mm) 4340 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 Distance from quenched end (sixteenths of an inch) 40 9840 4140 8640 50
Q1: Austenitized 40 mm diameter 5140 alloy steel bar is quenched in agitated oil. Predict what is the Rockwell hardness of this bar will be at (a) its surface and (b) its center (c) What do you think about the difference in hardness number between the center and surface (d) Differentiate between hardness and hardenability (e) Rank the steels in the figure below from lowest to highest hardenability and explain why. Cooling rate at 700°C (°C/sec) 300 150 011/3 55 100 600 Bar diameter (mm) 80 60 40 20 0 OLL 0 0 ww 25 12.5 8 5 S -------------- M-R 10 3/4-R Agitated oil 15 20 1/4 3/4 Distance from quenched end. De (Jominy distance) 5.5 4 3 Bar diameter (in.) 0 25 mm 1 in. Hardness (Rockwell C) Where (C = center, S = surface, M-R mid-radius) 65 60 55 50 45 40 35 30 25 20 15 10 0 10 1 20 Distance from quenched end (mm) 5140 1 30 L 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 Distance from quenched end (sixteenths of an inch) 4340 40 9840 4140 8640 50
Show microstructure of 8620 steel before homogenized annealing and microstructure after annealing.
I need the solution of this question please please please quickly Thanks
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