What happened The United States finally appears to be getting serious about addressing its aging infrastructure, and that has investors excited about U.S. Steel (NYSE: X). Shares of the steel giant climbed 57.6% in March, according to data provided by S&P Global Market Intelligence, in anticipation of growing government demand. So what Elected officials have been talking about infrastructure for a generation, but investors are buying into President Joe Biden's plan to rebuild American roads, ports, and bridges and update transit systems. Biden in March rolled out a nearly $1 trillion plan to modernize U.S. infrastructure, and it should mean a lot of added demand for steel. Image source: Getty Images. Investors are buying in ahead of the order flow. U.S. Steel shares are now up more than 200% in the last six months, including the strong March performance. Even without the added government demand, the outlook for steel and pricing has been improving as the economy reopens. U.S. Streel said mid-month it expects to earn $1.02 per share in the first quarter, better than the $0.72 consensus. BMO Capital analyst David Gagliano actually called that guidance "somewhat disappointing," given that he sees the current rally in steel prices extending into the second half of 2021. Now what U.S. Steel's stock price appreciation in recent months has been impressive, but a word of caution is needed. Industrial stocks tend not to sustain these sorts of jumps, and it appears after U.S. Steel's strong run, the upside is likely limited from here. The company received a number of downgrades to hold during the month on valuation. And Biden's infrastructure plan has a lot of hurdles to clear in Congress before it is law, with a lot of opportunities for the size to be cut or priorities changed. There is also some reason to question how much of the steel demand would be provided by U.S. producers, given the higher prices compared to imports. Be careful jumping on to this rally. 10 stocks we like better than United States SteelWhen investing geniuses David and Tom Gardner have a stock tip, it can pay to listen. After all, the newsletter they have run for over a decade, Motley Fool Stock Advisor, has tripled the market.* David and Tom just revealed what they believe are the ten best stocks for investors to buy right now... and United States Steel wasn't one of them! That's right -- they think these 10 stocks are even better buys. See the 10 stocks *Stock Advisor returns as of February 24, 2021 Lou Whiteman has no position in any of the stocks mentioned. The Motley Fool has no position in any of the stocks mentioned. The Motley Fool has a disclosure policy.Source