UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G Under the Securities Exchange Act of 1934* Quanex Corporation ---------------------------------------------------------------- (Name of Issuer) Common Stock ---------------------------------------------------------------- (Title of Class of Securities) 747620102 --------------------------------- (CUSIP Number) December 31, 1998 ---------------------------------------------------------------- (Date of Event Which Requires Filing of this Statement) Check appropriate box to designate the rule pursuant to which this Schedule is filed: [X] Rule 13d-1(b) [ ] Rule 13d-1(c) [ ] Rule 13d-1(d) *The remainder of this cover page shall be filled out for a reporting person's initial filing on this form with respect to the subject class of securities, and for any subsequent amendment containing information which would alter disclosures provided in a prior cover page. The information required on the remainder of this cover page shall not be deemed to be "filed" for the purpose of Section 18 of the Securities Exchange Act of 1934 ("Act") or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes). Page 1 of 4 Pages

- ----------------------- CUSIP NO. 747620102 13G - ----------------------- - ------------------------------------------------------------------------------ NAME OF REPORTING PERSON 1 S.S. or I.R.S. IDENTIFICATION NO. OF ABOVE PERSON Barrow, Hanley, Mewhinney & Strauss, Inc. 752403190 - ------------------------------------------------------------------------------ CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (See Instructions) 2 (a) [_] (b) [_] - ------------------------------------------------------------------------------ SEC USE ONLY 3 - ------------------------------------------------------------------------------ CITIZENSHIP OR PLACE OF ORGANIZATION 4 A Nevada corporation - ------------------------------------------------------------------------------ SOLE VOTING POWER 5 NUMBER OF 205,100 shares SHARES ----------------------------------------------------------- SHARED VOTING POWER BENEFICIALLY 6 549,400 shares OWNED BY ----------------------------------------------------------- EACH SOLE DISPOSITIVE POWER 7 REPORTING 754,500 shares PERSON ----------------------------------------------------------- SHARED DISPOSITIVE POWER WITH 8 -- - ------------------------------------------------------------------------------ AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 9 754,500 shares - ------------------------------------------------------------------------------ CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES 10 (See Instructions) [_] - ------------------------------------------------------------------------------ PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9) 11 5.3% - ----------------------------------------------------------------------------- TYPE OF REPORTING PERSON (See Instructions) 12 IA - ------------------------------------------------------------------------------ Page 2 of 4 Pages

SCHEDULE 13G - ------------ Item 1(a) Name of Issuer: Quanex Corporation 1(b) Address of Issuer's Principal Executive Offices: 1900 West Loop South Suite 1500 Houston, TX 77027 Item 2(a) Name of Person Filing: Barrow, Hanley, Mewhinney & Strauss, Inc. 2(b) Address of Principal Business Office or, if none, Residence: One McKinney Plaza 3232 McKinney Avenue, 15th Floor Dallas, TX 75204-2429 2(c) Citizenship: A Nevada corporation 2(d) Title of Class of Securities: Common Stock 2(e) CUSIP Number: 747620102 Item 3 If this statement is filed pursuant to Rules 13d-1(b), or 13d-2(b): The reporting person is an Investment Adviser registered under Section 203 of the Investment Advisers Act of 1940. Item 4 Ownership: 4(a) Amount beneficially owned: 754,500 shares 4(b) Percent of Class: 5.3% 4(c) Number of shares as to which such person has: (i) Sole power to vote or to direct the vote: 205,100 shares Page 3 of 4 Pages

(ii) Shared power to vote or to direct the vote: 549,400 shares (iii) Sole power to dispose or to direct the disposition of: 754,500 shares (iv) Shared power to dispose or to direct the disposition of: -- Item 5 Ownership of Five Percent or Less of a Class: Not Applicable. Item 6 Ownership of More than Five Percent on Behalf of Another Person: The right to receive or the power to direct the receipt of dividends from, or the proceeds from the sale of, the common stock is held by certain clients of the reporting person, none of which has such right or power with respect to five percent or more of the common stock. Item 7 Identification and Classification of the Subsidiary which Acquired the Security Being Reported on by the Parent Holding Company: Not Applicable. Item 8 Identification and Classification of Members of the Group: Not Applicable. Item 9 Notice of Dissolution of Group: Not Applicable. Item 10 Certification: By signing below the undersigned certifies that, to the best of its knowledge and belief, the securities referred to above were acquired in the ordinary course of business and were not acquired for the purpose of and do not have the effect of changing or influencing the control of the issuer of such securities and were not acquired in connection with or as a participant in any transaction having such purpose or effect. After reasonable inquiry and to the best of its knowledge and belief, the undersigned certifies that the information set forth in this statement is true, complete and correct. BARROW, HANLEY, MEWHINNEY & STRAUSS, INC. By: /s/ Bryant M. Hanley, Jr. Name: Bryant M. Hanley, Jr. Title: President February 11, 1999 Page 4 of 4 Pages