* Fed's Powell cites economic strength, downplays trade risks
* J&J gains on profit beat, boosts Dow and S&P 500
* Alphabet, Amazon and Facebook hit record highs
* UnitedHealth, Goldman drop on unconvincing profit beats
* Indexes up: Dow 0.22 pct, S&P 0.40 pct, Nasdaq 0.63 pct (Updates to market close)
By Stephen Culp
NEW YORK, July 17 (Reuters) - Wall Street stocks rose on Tuesday, with the Dow Jones Industrial Average posting its fourth consecutive session of gains after Federal Reserve Chairman Jerome Powell expressed an optimistic U.S. economic view and solid earnings bolstered the outlook for a robust reporting period.
In written statement Powell signaled that an era of stable economic growth may continue, but the Fed chairman was challenged in a congressional hearing by senators worried about the Trump administration's trade policies.
"(Powell) suggested that they're keeping an eye on trade developments and people are looking at that as a signal that they may moderate their rate increases if they see some signs of danger," said Peter Jankovskis, co-chief investment officer at OakBrook Investments LLC in Lisle, Illinois.
The U.S. Treasury yield curve hit its flattest in over a decade as Powell's upbeat economic view supported more rate hikes, with 2-year yields climbed to their highest in nearly a decade.
As the second-quarter earnings season shifts into high gear this week, analyst forecasts have grown rosier.
Analysts now see second-quarter S&P 500 earnings growth of 21.2 percent, up from 20.7 percent on July 1. Of the 39 companies in the index that have reported so far, 84.6 percent have come in ahead of Street expectations, according to Thomson Reuters data.
Earnings optimism was boosted by a report from the Federal Reserve showing an increase in U.S. industrial production led by a rebound in manufacturing.
"Economic reports ... are suggesting that activity in the second quarter might have been better than expected," Jankovskis said. "That, perhaps, is playing into some of these increases in forecasts."
The Dow Jones Industrial Average rose 55.53 points, or 0.22 percent, to end at 25,119.89, the S&P 500 gained 11.12 points, or 0.40 percent, to 2,809.55 and the Nasdaq Composite added 49.40 points, or 0.63 percent, to 7,855.12.
The Nasdaq's advance was led by Facebook Inc, Google-parent Alphabet Inc and Amazon.com Inc , all of which hit record highs.
Of the 11 major sectors of the S&P 500, seven ended the session in positive territory, with materials and technology seeing the strongest gains.
Johnson & Johnson led the healthcare sector's 0.5 percent advance, rising 3.5 percent after beating analysts' profit and revenue estimates.
Shares of Goldman Sachs Group Inc edged down 0.2 percent as the investment bank reported better-than-expected earnings and said David Solomon would replace outgoing CEO Lloyd Blankfein.
UnitedHealth Group Inc weighed the most heavily on the Dow, its shares down 2.6 percent as the largest U.S. health insurer reported higher-than-expected quarterly medical costs.
Netflix Inc regained ground, rising 5.2 percent after falling more than 14 percent following the streaming services company's reported shortfall in second-quarter subscriber additions.
Advancing issues outnumbered declining ones on the NYSE by a 1.39-to-1 ratio; on Nasdaq, a 1.38-to-1 ratio favored advancers.
The S&P 500 posted 25 new 52-week highs and one new low; the Nasdaq Composite recorded 82 new highs and 52 new lows.
Volume on U.S. exchanges was 6.00 billion shares, compared to the 6.54 billion average over the last 20 trading days. (Reporting by Stephen Culp Editing by James Dalgleish)