Advanced Placement US History (AP US History) 2025 – 400 Free Practice Questions to Pass the Exam

Andrew Carnegie is best known for revolutionizing the steel industry during the late 19th century. His innovative approaches to steel production significantly increased efficiency and lowered costs, allowing steel to become more accessible. Carnegie introduced the use of the Bessemer process in his mills, which enabled the mass production of steel and was crucial in meeting the growing demands of industrialization in the United States. This transformation facilitated the expansion of infrastructure, including railroads and buildings, positioning steel as a vital material in the nation’s economic development.

Carnegie's business practices, including vertical integration and philanthropy, further distinguished his impact on the steel industry. He would go on to create the Carnegie Steel Company, which eventually became one of the largest and most profitable steel companies in the world. His successes in this field laid the groundwork for the United States' emergence as a leading industrial power.