Name Chikara Nakao Birth Kyoto Japan Outline of

Name: Chikara Nakao Birth : Kyoto, Japan

Outline of Komatsu Establishment of Komatsu Net Sales Construction Equipment Sales Number of Employees Businesses: : May 13, 1921 : US$ 10. 2 Billion : US$ 6. 9 Billion : 28, 522 Construction & Mining Equipment Electronics Industrial Machinery Others *as of March 31, 2000 *All data is on a consolidated basis unless defined specifically.

Group Companies Komatsu UK (established in 1985) Durham Osaka plant Japan 87 companies The Americas 22 companies Europe, Middle East and Africa 15 companies Asia and Oceania 18 companies 142 consolidated companies Head office Tokyo

930 E Payload capacity 290 tons Flywheel horsepower 2, 500 HP(1, 865 k. W)

Board of directors Head office administration Administration Dept. Research Division Manufacturing Awazu Plant Engineering Development Center Materials Development Group Production Division Developing Division Process Development Group Osaka Plant System Development Group Oyama Plant

Heat treatment for Hydraulic Excavator

Al mass% Dispersion of Aluminum Nitride by carbonitriding process in Al containing Steels 1. 0 0 1 N mass ppm 2 Solubility of Al. N in Austenite

Gas Carburizing Carbonitriding 40 20 min 4. 0 H CP=1. 3 CP=0. 8 (CH 3 OH+C 3 H 8) (CH 3 OH+C 3 H 8 + NH 3) { CP: Carbon potential NH 3 = 1 3 N 2+ H 2 2 2 3 NH 3 = N+ H 2 2

Microstructure (5% nital)

%N Nitrogen profile (EPMA) Distance from surface

Nitride precipitates layer x Effects of Al content on nitride precipitates layer A Low Al steel B Medium Al steel C High Al steel

Wager's internal oxidation equation CN C (mol/m 3) d C N dx ( 0 ) C Al -DN = dx dt S N N 0 x x (m) At x=x, consumption of Al is equal to nitrogen supply. d CN @ dx S CN ÉÃ

Experimental x Low CNS Low Al content Medium Al content High Al content 0 0 Calculated x

Numerical analysis of N and Al distribution Concentration Al N Distance from surface

Prediction of hardness, stress, and stain in various conditions Input Shape, chemical composition of steel, Jominy curve, CCT data. . Calculation (FEM) Carbon diffusion, thermal calculation, elasto-plastic analysis Output Carbon distribution, hardness, microstructure, stress, distortion. .

Calculation of carburizing and quenching e ite ns nit ste Au rte Ma tensional com sive s pre Bainite Carbon distribution Microstructure ( 20 sec after quenching) Steel : SCM 420 H Hardness profiles Residual stress distribution 930 C (Fe-0. 21 C-0. 25 Si-0. 73 Mn-0. 1 Ni-1. 0 Cr-0. 25 Mo) Heat-treatment : Carburizing 5 h 850 C 1 h 1 h