Name: Chikara Nakao Birth : Kyoto, Japan

Outline of Komatsu Establishment of Komatsu : May 13, 1921 Net Sales : US$ 10.2 Billion Number of Employees : 28,522 Construction Equipment Sales : US$ 6.9 Billion Businesses: Others *as of March 31, 2000 *All data is on a consolidated basis unless defined specifically. Construction & Mining Equipment Electronics Industrial Machinery

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

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

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

Heat treatment for Hydraulic Excavator

Dispersion of Aluminum Nitride by carbonitriding process in Al containing Steels Al mass% N mass ppm Solubility of AlN in Austenite

20 min 4.0H (CH 3 OH+C 3 H 8 ) (CH 3 OH+C 3 H 8 + NH 3 ) 40 min CP=1.3CP=0.8 CP: Carbon potential NH 3 = N 2 + H NH 3 = N+ H { 2 1 Gas Carburizing Carbonitriding

Microstructure (5% nital)

Nitrogen profile (EPMA) %N Distance from surface

Nitride precipitates layer  B Medium Al steelA Low Al steelC High Al steel Effects of Al content on nitride precipitates layer

Wager's internal oxidation equation S N C  d N N )0( Al C -D C d x dd = d t x d N C d x   S N C At x= , consumption of Al is equal to nitrogen supply. 0 N C (mol/m 3 ) (m) N

0 0 Calculated  Experimental  Low Al content Medium Al content High Al content High C N S Low C N S Low Al content Medium Al content High Al content

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

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....

Hardness profiles Carbon distribution Residual stress distribution Microstructure ( 20 sec after quenching) Bainite Martensite Austenite Calculation of carburizing and quenching compressive tensional 930C 5h 1h 850C Steel : SCM420H (Fe-0.21C-0.25Si-0.73Mn-0.1Ni-1.0Cr-0.25Mo) Heat-treatment : Carburizing