July 30 (Reuters) - Tata Steel reported a bigger-than-expected rise in first-quarter profit on Wednesday as India's second-biggest steelmaker by market capitalization was helped by lower raw material costs that boosted margins.

Its consolidated net profit more-than doubled to 20.78 billion rupees ($236.8 million) in the quarter ended June 30, above analysts' estimates of 18.13 billion rupees, according to data compiled by LSEG.

Analysts had expected lower prices of iron ore and coking coal, essential raw materials for steel producers, to help boost profitability for steel makers.

The company's total expenses declined by about 4% to 503.47 billion rupees, primarily due to a drop of 12.7% in the cost of materials consumed, which accounts for more than 30% of its total expenses.

While domestic steel prices were still lower than a year ago, they saw a quarter-on-quarter improvement after the government introduced a temporary 12% safeguard duty in April to counter a surge in low-cost imports, particularly from China. Analysts had anticipated that the measure would help boost local prices and protect margins.

Tata Steel's net profit margin improved to 3.77% from 1.68% a year ago.

The Tata Group company said its total revenue from operations fell about 3% to 531.78 billion rupees, while analysts' expected revenue of 515.18 billion rupees, according to data compiled by LSEG.

Tata Steel's consolidated production volumes  fell 8.4% and delivery volumes dropped 3.7% year-on-year, due to maintenance related shutdowns in its Jamshedpur blast furnace and Neelachal Ispat Nigam. The company expects production and deliveries to normalise in the coming quarters.

Earlier in the month, larger rival JSW Steel also beat first-quarter profit estimates on easing raw material costs but flagged concerns of cheaper steel imports.