This week, four Metals and Mining stocks are improving their overall ratings on Portfolio Grader. Each of these stocks is rated an “A” (“strong buy”) or “B” overall (“buy”).

Reliance Steel & Aluminum (NYSE:RS) is bumping up its rating from a C (“hold”) to a B (“buy”) this week. Reliance Steel & Aluminum operates as a metals service center company in North America. Shares of RS have increased 9.2% over the past month, better than the 3.1% increase the S&P 500 has seen over the same period of time. For more information, get Portfolio Grader’s complete analysis of RS stock.

RTI International Metals (NYSE:RTI) boosts its rating from a C to a B this week. RTI International Metals manufactures and distributes titanium and specialty metal mill products, extruded shapes, and engineered systems. Wall Street has pushed the stock higher by 8.2% over the past month. For more information, get Portfolio Grader’s complete analysis of RTI stock.

This week, Worthington Industries (NYSE:WOR) is showing good progress as the company’s rating jumps from a B (“buy”) last week to an A (“strong buy”). Worthington Industries is a company in the metals processing industry that focuses on steel processing and manufactured metal products. For more information, get Portfolio Grader’s complete analysis of WOR stock.

The rating of Southern Copper (NYSE:SCCO) moves up this week, rising from a C to a B. Southern Copper is an integrated copper producer. For more information, get Portfolio Grader’s complete analysis of SCCO stock.

Louis Navellier’s proprietary Portfolio Grader stock ranking system assesses roughly 5,000 companies every week based on a number of fundamental and quantitative measures. Stocks are given a letter grade based on their results — with A being “strong buy,” and F being “strong sell.” Explore the tool here.