I was a supporter of Bernie and he planned to do the same thing, for basically the same reasons. He didn't pick this unilaterally either, the Commerce department recommended it.
I can't find evidence that Bernie advocated tariffs at these levels. I know he spoke against "unfettered free trade" and new agreements like TPP, but I remember him talking more about taxing the import of labor (US companies using foreign labor) more than materials (US companies importing goods).
It also looks like the Commerce Dept was staunchly against this idea in 2016[1].
1. https://news.vice.com/article/trumps-views-on-trade-are-clos...
[1][His campaign says Sanders also would impose countervailing tariffs on imports from China and Japan “until they stop dumping steel into the United States and stop manipulating their currencies.”]
1.https://www.usatoday.com/story/news/politics/onpolitics/2016...
Trump/Bernie very close on trade policy: http://www.politifact.com/north-carolina/statements/2016/jul...
Both of them appealed strongly to blue collar workers because these positions on trade, Sanders would have won hands down against Trump if not for the rigged primaries.
IIRC, Biden has a similar mindset, and definitely can speak to Trump’s base in a way that Clinton (“deplorables”...) could not. Of the dem contenders so far, he’s the best chance of winning in 2020 imo.