No. Unfortunately, there is no extension to pay your federal 2018 quarterly individual estimated tax payments.
According to IRS: "For estimated tax purposes, the year is divided into four payment periods. Each period has a specific payment due date. If you don't pay enough tax by the due date of each payment period, you may be charged a penalty even if you're due a refund when you file your income tax return at the end of the year.
If you mail your estimated tax payment and the date of the U.S. postmark is on or before the due date, the IRS will generally consider the payment to be on time. If you use IRS Direct Pay, you can make payments up to 8 p.m. Eastern time on the due date. If you use a credit or a debit card, you can make payments up to midnight on the due date.
When to Pay Estimated TaxPayment PeriodDue DateJanuary 1 – March 31April 15April 1 – May 31June 15June 1 – August 31September 15September 1 – December 31January 15* of the following year. *See January payment in Chapter 2 of Publication 505, Tax Withholding and Estimated TaxFiscal Year TaxpayersIf your tax year doesn't begin on January 1, see the special rules for fiscal year taxpayers in Chapter 2 of Publication 505Farmers and FishermenSee Chapter 2 of Publication 505Note: If the due date for making an estimated tax payment falls on a Saturday, Sunday, or legal holiday, the payment will be on time if you make it on the next day that's not a Saturday, Sunday, or legal holiday."
https://www.irs.gov/faqs/estimated-tax/individuals/individuals-2
