e894as5h

# e894as5h - ESNC 460/894 Assignment 5 Apr 1 2005 due Apr 11...

This preview shows pages 1–7. Sign up to view the full content.

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: ESNC 460/894 Assignment 5: Apr. 1, 2005 due Apr. 11, 2005 1(a) Using the energy balance approach, estimate the power required to produce a spot weld 3mm in diameter and 1 mm deep in low—carbon steel with a 1 sec pulse from a C02 laser. Use p = 7.86 gi’cm3 . 0t 2 0.07 ClTllfS, C = 0.? jng, k = 0.4 Wich. Tm = [8090K Li 2 13.8 kJJ‘mul, R=609ir (b) Compare the depth given in part (a) with the thermal penetration depth predicted on the basis of the uniform irradiance mode]. Remember. at this depth the temperature is only about 35% of the surface temperature. (c) According to the uniform irradiance model. how long does it take to reach T"1 at the surface for the power in (a)? .4 I r I I - if, - 7/ ' ,1 .— mam-HI I a W .l: , wme . 3, mum: —— ' QETMT v 1 / dil’imml— _u_ . — 3 A —1 SI‘_ / 2 Low carbon steel of 5 mm thickness is to be cut with a laser at :1 Speed of 1.25 mimin. with a 0.5 mm kert‘. Using energy balance, estimate the power that must be coupled into the material. Use 9 = 7.36 giam‘ , 0: = 0.07 cmzfs. c = 0.50 tigK. k = 0.4 wxch. T... = 18090; L. = 13.8 klfmol, L. = 350 kJi’mol. T. = 3135“K. R=609i 3 Mild steel is to be welded Wilh a multi—kilowatt C0; laser. Using the model of Swift—Honk and Giek, estimate the power required to produce a weld 0f2 mm width and 4.5 mm depth at l mfmin. o: = 0.09 cnﬂs. k = 0.4 Wich, Tm z 1809°K 4 Ileles are to be drilled in 0.5 mm thick nickel with a diameter of 0.13 mm. using a pulsed Nd:YAG laser with a 4 kW peak power output. Use energy balance equations to estimate the energy needed and the pulse length, assuming a nearly square pulse in time. Show that the time to reach vaporization at the surface is very small, based on the results of the uni form irradianee model. [3 = 8.9 glem" . C = 0.44 Jng, k = 0.91 WtemK, T”1 = 1726°K. Lr = 298 Jig. Lv = 6303Ji’g, 'I‘r : 318?°K. R2609? —mn5x.. 1 . y,- , —.-. .1112 1 "17% i. . ml! Elﬁlﬂ , m 5 , L ' ,‘I _i' W .t ,. '19:! J ...
View Full Document

{[ snackBarMessage ]}

### Page1 / 7

e894as5h - ESNC 460/894 Assignment 5 Apr 1 2005 due Apr 11...

This preview shows document pages 1 - 7. Sign up to view the full document.

View Full Document
Ask a homework question - tutors are online