<ARTICLE> 5
<MULTIPLIER> 1,000
       
                             
<PERIOD-TYPE>                   6-MOS
<FISCAL-YEAR-END>                          DEC-31-1997
<PERIOD-END>                               JUN-30-1997
<CASH>                                           67289
<SECURITIES>                                         0
<RECEIVABLES>                                    83542
<ALLOWANCES>                                         0
<INVENTORY>                                     109893
<CURRENT-ASSETS>                                299635
<PP&E>                                          504552
<DEPRECIATION>                                  251969
<TOTAL-ASSETS>                                  686484
<CURRENT-LIABILITIES>                           112129
<BONDS>                                              0
<PREFERRED-MANDATORY>                                0
<PREFERRED>                                          0
<COMMON>                                           282
<OTHER-SE>                                      415176
<TOTAL-LIABILITY-AND-EQUITY>                    686484
<SALES>                                         360235
<TOTAL-REVENUES>                                360235
<CGS>                                           272230
<TOTAL-COSTS>                                   329674
<OTHER-EXPENSES>                                 (286)
<LOSS-PROVISION>                                     0
<INTEREST-EXPENSE>                                1765
<INCOME-PRETAX>                                  29082
<INCOME-TAX>                                     11850
<INCOME-CONTINUING>                              17232
<DISCONTINUED>                                       0
<EXTRAORDINARY>                                      0
<CHANGES>                                            0
<NET-INCOME>                                     17232
<EPS-PRIMARY>                                     0.60
<EPS-DILUTED>                                     0.60